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HINRICHS' 

ELEMENTS OF CHEMISTRY 

AND MINERALOGY. 



Diese Wissenschaft lasst sich nicht aus Biichern, noch aueh allein durch Besuch 
von chemischen Vorlesungen, sondern nur durch tleissiges Arbeiten im Laborato- 
rium erlernen. 

Hermann Kolbe, 

(TraadatdoD, gee ct»p. vin.) Dii'- Chem. Lab. Univ. Leipzig. 



THE ELEMENTS 



OF 



PHYSICAL SCIENCE, 



DEMONSTRATED BY 



THE STUDENT'S OWN EXPERIMENTS 
AND OBSERVATIONS. 



BY 

GUSTAVUS HINRICHS, A. M 



IN THREE VOLUMES. 



VOLUME II. 

THE ELEMENTS OF CHEMISTRY 

AND MINERALOGY. 

WITH TWO PLATES AND JOURNAL OF EXPERIMENTS. 



DAVENPORT, IOWA, U. S. 
PUBLISHED BY GRIGGS, WATSON, & DAY. 

LEIPZIG : F. A. BROCKHAUS. 

1871. 



THE 



ELEMENTS OF CHEMISTRY 



AND MINERALOGY, 



DEMONSTRATED BY 



THE STUDENT'S OWN EXPERIMENTS. 



BY 




GUSTAVUS f HINRICHS, A. M. 

Professor of Physical Science in the State University of Iowa; Member, or 

Correspondent, of Scientific Societies at Berlin, Vienna, 

Koenigsberg, Emden, etc., etc. 



WITH TWO PLATES 

AND JOURNAL OF EXPERIMENTS. 



DAVENPORT, IOWA, U. S. 
PUBLISHED BY GRIGGS, WATSON, & DAY. 

LEIPZIG : P. A. BROCKHAUS. 

1871. 



Entered according to act of Congress, in the year 1871, by 

GUSTAVUS HINRICHS, 
In the office of the Librarian of Congress, at Washington. 



riie right of translation and re-publication reserved 
^^ n. ^° hv tU« author. 

X s 



/ 17 



PREFACE TO VOL. I. £/ 



It is generally understood by those qnaliftad to judge, that the teach 
ing of elementary science in our schools is not carried on in a scien 
tific spirit. Recitation from a text book, with occasional exhibition 
of experiments and specimens, is not calculated to give the beginner 
conviction in the truth stated, or to initiate him into the method of 
scientific investigation. 

In regard to science, our schools are not above the middle ages. 
Three hundred years ago students repeated the obscure statements of 
Aristotle, of which a sample is given e454) ; now our students repeat 
the statements of their text book, without obtaining any valid ground 
for the conviction they are made to express. 

The great work done by Galileo for- physical science in general t 
has not yet reached our schools. The method of scientific research 
which he first so successfully practiced, and which alone can lead to 
conviction in the truth of the resuitStObtained, has not yet gained admis- 
sion to our schools. 

We venture with the present little work to knock at the doors of 
our schools in behalf of this method and in the interest of science. 
AVe do not advocate anything new. For two and a half centuries 
these very methods have been used, the grand structure of modern sci- 
ence has resulted, and the course of civilization has been changed 
thereby. 

That these same methods art successful in the school room and with 
beginners, is not a mere conclusion, but a fact established by experi- 
ence. The few series of experiments printed in the "Journal" of 
this volume will confirm it. The series here published have been 
taken from an immense material already accumulated by students in 
our laboratory. 

.But this work is so thoroughly different from those which are in 
general use, that we feel under great obligations to the Publishers for 
having ventured this publication. 

Before attempting the use of this book, the student, and especially 
the tsaclter, should carefully study the Guide at the close of this volume. 

Iowa City, Iowa, U. S., January, 1871. 



PREFACE TO VOL. II, 



These Elements of Chemistry and Mineralogy form simply a con- 
tinuation of an Elements of Physics. 

Laboratory practice in chemistry is universally recognized as essen- 
tial ; but it cannot become universal, if grand laboratories with costly 
apparatus are required. By excluding special and professional branches, 
the methods of elementary laboratory practice here given can be fur- 
nished free of charge by any school to all its pupils. See Chapter 
VIII. of this volume, for details. 

No one should judge our chapter on mineralogy except after having 
tried it in precisely the manner directed. The determination by co- 
ordinates is novel, and quite satisfactory. 

While writing these lines, we receive the very cordial welcome 
which the London " Nature " extends to the first volume of this course 
in the Elements of Physical Science. We have earnestly endeavored, 
also, in this second volume, to "point out the right path of discovery " 
to the student, and to "act on the whole as a faithful and thoroughly 
painstaking guide." If " Nature," upon examination of this second 
volume, gives it an equally cordial welcome, we shall feel encouraged, 
while amidst but too many difficulties we prepare the final revision of 
the concluding volume of these Elements of Physical Science — The 
Students' Cosmos. 

Iowa City, U. S., Oct. 21, 1871. 



CONTENTS. 



CHAPTER L— On Heat. 
I. Modes of Heating 
II. Radiation and Condensation 

III. Thermometer and Calorimeter 

IV. Fusing and Boiling 
CHAPTER II.— Heat and Mechanical Work 
CHAPTER III.— Dissociation and Electrolysis 
CHAPTER IV.— Elements and Compounds. 

I. The Elements .... 
II. Chemical Nomenclature 
CHAPTER V.— Acids and Bases 
CHAPTER VI.— Chemical Processes. 

I. Reactions .... 

II. Synthesis .... 

III. Substitution .... 

IV. Double Decomposition 
V. Complex Processes 

CHAPTER VII.— Elements op Mineralogy. 
I. Classification and Determination 
II. Descriptive Mineralogy 
CHAPTER VIII.— The Chemical School Laboratory 
Student's Journal of Experiments . 



2 
10 
13 

21 

33 

46 

57 
66 

72 



91 

94 

102 

112 

117 
129 
156 
163 



CHAPTER I. 



ON HEAT. 



1. The S u n is our principal source of heat. 

The heat obtained by combustion of wood and of 
other vegetable materials is also due to the sun ; for plants 
require sunshine in order to grow. 

2. Heat effects very remarkable changes in the sub 
stances upon which it acts.* These effects of heat may 
be classified as changes involume, changes in aggre- 
gation, and changes in compositi on. 

3. That heat effects changes in volume is a matter 
of common experience, and may also be shown by the fol- 
lowing apparatus, called a thermometer. 

A glass or tin flask, of about 25 cc. capacity is com- 
pletely filled with water, and closed by a stopper through 
which passes a narrow, long tube ; as the stopper is pressed 
down, the water rises in the tube. A centimeter scale, 
divided to halves, is attached to the tube. If now the 
flask is placed in a vessel containing hot water, the 
level of the water in the tube will rise. If thereafter, the 
flask is put into cold water, or surrounded by iee t the level 
will sink. 

The rise and fall of the level evidently constitutes a 
change in the volume of the water, brought about by the 
heat added to, or taken away from the flask. 



*The effects on our own orgaodsin, especially the production of the sensation of 
warmth, cannot be considered in, the elements of physical science. 



Chapter I. 



4. That heat produces changes in aggregation has 
already been demonstrated in the Elements of Physics. 
Articles 113 and 151. 

The solid i c e is by heat fused to liquid w a t e r, and 
the latter by additional heat changed into gaseous steam. 
By removing heat, steam is again condensed to water, and 
water frozen to ice. Iodine also is readily exhibited in 
these three states of aggregation by applying or removing 
heat. (Elements of Physics. 113.) 

5- A crystal of blue vitriol gently heated in a glass tube 
changes to a white powder, while the colder parts of the 
glass tube become covered with numerous drops of water. 
In this case heat has changed the state of combination, 
the blue vitriol being resolved inlo a white powder and 
water. 

6. Such changes in the composition of substances are 
often termed chemical processes. Changes in volume 
and aggregation, not affecting the composition of bodies, 
are distinguished as p h y s i c a 1 processes. 

These latter processes shall be studied in the first two 
chapters, while the chemical processes will be treated of 
in the balance of this volume. 

7. To study these different effects of heat experiment- 
ally, we must first become familiar with the various modes 
of applying heat for experimental purposes. 

I. MODES OP HEATING. 

8. For the student's experiments, the flame of a g 1 a s s 
alcohol lamp is a sufficient source of heat. For the 
blow-pipe, a common candle may replace this lamp. 

Illuminating gas, burnt in a Bunsen burner, is better 
than the above, but not everywhere accessible. If used, 
its flame should be turned down until suitable for the 
small quantities to be heated. 

9. The substances to be heated are supported over 
the flame in vessels of glass, porcelain, or plati- 



Modes of Heating. 



n u m. The vessels are either exposed to the heat direct 
or by means of sand b a t h, air bath or water 
bath. Charcoal is extensively used as support when 
the blow-pipe flame is to be applied. 

10. No experiment can give a satisfactory result, unless 
it is performed exactly as directed. But to understand 
the directions, the student must be perfectly familiar with 
the terms used to designate the various forms of appara- 
tus employed. Hence the student should carefully study 
the following pages. * 

11. The glass alcohol lamp should contain good 
alcohol, and be provided with a sufficiently long, well- 
trimmed wick. At the close of the experiment, the flame 
is extinguished by blowing, and the closely-fitting glass- 
cap is put on to prevent the evaporation of the alcohol. 

Carefully avoid the soiling of the wick or its support, so 
that the lamp burns with a pure, pale flame. 

12. The Bunsen burner consists of a narrow, vertical 
gas-jet, surrounded by a vertical brass tube one centimeter 
in diameter, and partly open below. The flame formed at 
the top of the wide tube results from the combustion of the 
intimate mixture of gas and air formed in the wider tube. 

This flame of the Bunsen burner is but faintly lumin 
ous, but intensely heating, and free from s o o t, so as 
to leave apparatus exposed to it clean. The common gas 
burners give a highly luminous flame, which deposits 
much soot, and hence cannot be used for experiments on 
heat. 

13. The glass vessels used as support for substances to 



*Ifc is expected that the teacher exhibit these apparatus to the class while this 
subject is under consideration. 

Since the student of course has to pay the cost of all apparatus he breaks, as well 
as the cost of the material he wastes by improper work, he will save himself much 
money by a very careful study of this section prior to his beginning the experi- 
ments of the next section. Besides, by avoiding breakage and waste, the student 
will not delay the experimental work of his fellow-students, nor cause his teacher 
additional trouble and'vexation. 



Chapter I. 



be heated, are, retorts, flasks, beakers, dishes, 
watch glasses, test tubes, and common glass 
tubes. These will readily be distinguished and described 
by the student, while the teacher exhibits thern to the 
class. 

All these glass vessels must be thoroughly annealed, 
and of uniform thickness, in order to withstand moder- 
ately sudden changes of heat. 

They should be scrupulously washed ( with common 
water*) and rinsed (with distilled water) immediately 
after and again before use. Those outer parts which 
are to be exposed to the direct influence of heat, should 
furthermore be wiped dry, in order to avoid breakage from 
the flame ( or heated sand. See 18). 

14. For our purposes a glass flask of 25 to 50 cc. 
capacity, a few watch glasses (5 cm. diam.), and three or 
four test tubes ( 1 cm. diam., 7 or 8 cm. long) 
are quite sufficient. A few lengths of glass tubing will 
also be required — some 3 mm. internal diameter, for 
blow-pipe work, and some 5 mm. internal diameter, for 
other work, such as distillation, etc. 

15. Crucibles and dishes of porcelain are 
very useful, but not necessary for beginners, since tire 
blow-pipe and glass tube may be substituted for the cru- 
cible, and the watch glass for the dish. Still, the teacher 
may exhibit some of the forms of porcelain ware in use 
in laboratories. 

16. Platinum is used, as support for substances to be 
heated, in the shape of c r u cib 1 es, d i s h es, foil, 
strips, and wire. Only the last three forms are re- 
quired by the beginner in blow-pipe work. 

We shall therefore defer the description of these forms 
of platinum until we take up the description of the blow- 
pipe, when the charcoal support also will be noticed. 

♦Aided by washers, consisting of a piece of sponge tied to a small stick, or 
pieces of paper shaken in the flask until the paper is reduced to a pulp. 



Modes of Heating. 



17. A glass vessel to be heated is but rarely exposed 
to the direct flame by supporting the vessel on a triangle 
of iron wire^above the flame. It is best to place the glass 
vessel on a square piece of ( brass ) w i r e-g auze, which 
really prevents the flame from striking the glass vessel. 
This property of a wire-gauze may be exhibited by pres- 
sing such a gauze down upon a flame ; the flame will 
then appear as if cut off by the gauze. 

18. Beginners will always do well to support the glass 
vessel on a sand bath, rather than over the direct flame, 
or even the gauze. 

A sand bath consists simply in a thin, shallow, sheet- 
iron dish, partly filled with coarse sand, which has been 
freed from dust by washing and drying. 

19. If but a moderate heat is required, or if it be 
essential to prevent the heat from rising 
above that of boilingwater, the water bath 
is used. 

In its simplest form the water bath consists of a tin 
cup, about 10 cm. in diameter and 6 cm. high, closed by 
a cover provided with a circular opening of about 5 cm. 
in diameter. Before use, the bath is filled about two- 
thirds full with water, placed over the flame, and the vessel 
to be heated put over the opening in the cover. 

The student should be very careful to see that the 
water in the water bath does not get too low. 

20. The airbath is a vessel of iron or copper,, 
wherein the apparatus to be heated may be placed while 
the air bath is exposed to a flame. The beginner does not 
require this bath. 

21. The preceding modes of heating correspond to 
the application of heat by boilers, stills, and retorts, in 
the arts. In none of the above cases is an excessive de- 
gree of heat produced. But in the various furnaces so 
extensively used in the arts, very high degrees of heat 
result. To imitate these furnaces on a small scale for 



Chapter I. 



experimental purposes, the blow-pipe is used in the labora- 
tory. 

22. The blow pipe is a small, bent tube, used to 
produce a line jet of air, by means of which a flame is 
blown aside so as to concentrate its hear in a small space. 

The best form of blowpipe, as represented in figure 
1, cunsists of five parts. The m out h-p i e c e, a, is of 
horn ; the main tube, b, a i r-c liaiuber, c, and main 
j e t, d, are of brass or German silver, while the jet proper, 
e, is of platinum. This latter is represented in full size 
in a section below d, in the figure. The metallic pieces 
fit into one another with gentle friction, and may betaken 
apart ; only the mouth-piece, a, is firmly attached with 
sealing wax to the tube, b. 

The hole in the platinum jet is very fine. By proper 
care it never gets clogged ; but, if it should get stopped 
in the hands of the beginner, the jet should be given to 
the teacher to be burnt out.* Never touch anything 
with the platinum jet, except the flame. 

23. It "is not very difficult to learn to blow if the fol- 
lowing directions are carefully obeyed : 

Firmly close your lips, distend the cheeks as widely as 
possible, and breathe slowly, regularly, and deeply through 
the nostrils alone — always keeping the cheeks fully dis- 
tended during inhalation as well as during exhalation. 

When you can do this for several minutes at a time, 
grasp the blow-pipe tube firmly with the right hand and 
press the mouth piece against your lips. Support the tube 
on the thumb, third and fourth fingers, while the first and 
second fingers press the tube against the former just be- 
low the ring, f, on the tube. Thus the tube will be held 
firm as by a vise, and without special effort. See figure 2. 

Bring the jet almost into the flame of a candle, f or 

*It must never be drilled out. 

+ The wick of which has been bent asid6 in the direction of the jet. 



Mode* of Heating. 



alcohol lamp ; you will then see it blown aside, as shown 
in figure 3. Continue to keep this blow-pipe flame 
steady, firm, and of the shape of a sharp cone. The flame 
must be kept as steady as if it were a solid body. Hold, 
by means of your left hand, a piece of iron wire ( about 
one fourth of a millimeter thick) in the luminous 
point, b, of the blow-pipe flame. You will thus be able 
to see whether your blow-pipe flame is steady or flickering. 
Practice this experiment until you can keep the flame 
steady, at least during one minute. 

The iron wire then- will fuse, and burn often with scin- 
tillations; thus proving that the heat in the point 
of the bio w-p ipe flame is very intense. 

24. By close inspection you will notice that the most 
luminous point, b, of the blow-pipe flame is really but the 
vertex of a hollow luminous cone, indicated by the shaded 
portion in figure 3. This point of greatest heat is 
also termed the fusing point or f using regio n of 
the blow-pipe flame. 

This bright, luminous cone is surrounded by a faint hol- 
low cone of light, c, termed the outer flame of the 
blow-pipe. Inside of the bright hollow cone is the inner 
flame, d, of the blow-pipe. 

These three regions of the blow-pipe flame have very 
different properties ; hence the great importance of learn- 
ing to keep the flame perfectly steady, so that only one of 
these regions acts upon the object. The abbreviations, 
o-fl. and i-fl. are often used to denote respectively the 
outer, c, and inner, d, blow-pipe flame. 

25. On the smooth surface of a piece of c h a r c o a If 
a small piece of lead — about one or two centigrams — 
is placed, as indicated in figure 4. Heated in the out- 
er flame the lead fuses, partly volatilizes and burns, 

fBy means of a saw the charcoal is cut into blocks about 5 cm, wide, 10 cm. long 
and 2 cm. thick. The surface to be used is sm.oth.ed with a knife — over a tin box, to 
receive the dust. Be careful to keep your ringers clean. 



Chapter I. 



covering the charcoal with a well defined, elliptical i ti- 
er natation of a yellowish color. Perfect definition 
of this incrustation is a good test for perfect steadiness^of 
the flame. 

If you, thereafter, direct the inner flame upon any part 
of the incrustation, j t ou will in a few instants convert k that 
part of the incrustation into minute globules of metallic 
lead. 

From this it appears that the i-fl. and o-fl. have oppo- 
site properties. Since the inner flame reduces the 
incrustations again to metallic lead, this part of the flame 
is oiten called the reducing flame. -^The outer flame, 
then, is termed the oxidizing flame. 

26. Besides the charcoal-support here spoken of, we 
use platinum and glass-tube supports for substances to be 
heated in the blowpipe flame. 

The platinum supports are the foil, the strip, 
and the wire. The platinum foil is a triangular 
piece of thin sheet platinum, about 1.5 cm. wide at the 
base, and 3 cm. long. For use, its vertex is held by a 
pair of steel tweezers,* or by inserting the vertex in a 
partly split-up match. 

The platinum strip is cut from the same sheet 
platinum, and is about one mm. wide, three or five cm. 
long. It is held in the same manner as the foil. 

The platinum w i r e is about half a millimeter thick 
and as long as the strip. One end of this wire is bent 
into a circular 1 o o p of about two mm. diameter, by 
twisting the wire around the platinum jet of the blow- 
pipe. 

27- The platinum foil is used for f u s i o n a n d fl u x_ 
i n g, being heated from below. The platinum strip is 
used for fl a m e-c o 1 o r a t i o n s ; the wire-loop for borax 



*A small ring sliding along the tweezers keeps these shut so as to hold the foil 
firmly without special effort on the part of the student. 



Modes of Heating. 



b e a d 8. These different applications may be exhibited 
by the teacher before the class. 

We shall, in the following, return more fully to this 
subject. For practice the student may simply heat 
the platinum as indicated : the foil from below, the strip 
at the fusing point, and the loop at the same point, but in 
such a manner that the flame passes through the loop at 
right angles to the plane of the same. 

When these platinum pieces are first inserted into the 
fusing point of the flame they usually tinge the outer 
flame yellow. After some heating this color disappears, 
the outer flame becoming colorless. If you now touch 
the cooled strip with the so-called carefully cleaned fin- 
ger, you will see the yellow color reappear upon re-heat- 
ing the strip — thus proving that the carefully cleaned 
fingers contain something ( salt ) which tinges the flames. 

This fact also shows the necessity of most careful clean- 
ing* of the platinum wire. 

Certain substances fusing readily together with platinum, 
it is important that the student should use the platinum 
only when expressly directed, in order to prevent the 
loss of this expensive metal. 

28- The glass s u pp or t for blow-pipe use consists 
in a narrow ( 3 mm. wide ) glass tube, 5 cm. long, 
either closed at one end or open at both ends. In the 
former case (closed tube) heat alone can act upon the 
substance in the tube, the air being practically excluded 
as well as in a covered crucible. In the open tube a 
current of air necessarily passes along the tube, especially 
if the latter is held obliquely. 



♦This is accomplished by first fusing some sodium bisulphate on the platinum, 
then dissolving the fused mass with water, assisted by gentle friction, if need be,— 
followed by thorough washing and rinsing with water. Potassium bisulphate an 
swers equally well. 

The platinum strip and foil should also be kept smooth. To smoothen the 
foil or strip, hold them on a clean piece of glass, and repeatedly push the nail 
of a finger along the platinum in one direction only. 

2 



10 Chapter I. 



For the purpose of practice, a minute fragment (one or 
two cgr.) of pyrite may be heated in each of these tubes, 
and the results noted. 

29. To succeed well with the blow-pipe, it is not suf- 
ficient to be able to produce a steady blow-pipe flame, and 
to apply constantly that region which is to be used ; it is 
equally essential to take but a minute quantity of the 
substance to be acted upon. One centigram will in 
most eases prove quite sufficient. The test object should 
hardly ever measure more than a millimeter in any direc- 
tion. 

30- It will have been observed that precisely the same 
modes of heating here described are in constant use on a 
large scale in the arts. In these experiments only minute 
quantities being used — but in the arts the same operations 
often are performed on tons at a time. 

Now it is true that the properties of a substance do not 
depend upon the absolute amount of the substance. See 
Elements of Physics, article 111. But at the same time 
the use of minute quantities in experi- 
mentation makes extreme care and clean- 
liness absolutely imperative, if the properties 
are to be distinctly and unmistakably recognized by the 
student. 

II. RADIATION AND CONDUCTION. 

31. The simple apparatus described in article 3, 
constitutes a thermometer, if it is provided with a 
centimeter scale ;* for the higher the column of water in 
the tube, the greater the degree of heat. We shall make 
use of this exceedingly simple thermometer to demon- 
strate the law of cooling, and the principal facts in regard 
to radiation and conduction. 



*A strip of card paper one centimeter wide, divided into centimeters and halves, 
attached to the tube by a few loops of thread and some sealing wax to keep it in 
place, will answer well enough 



Radiation and Conduction. II 



The height of the column of water expressed by the 
number on the scale is called the temperature, or 
degree of heat of the water in the thermometer. 

32. If the thermometer is heated on the water bath 
and thereafter exposed to the air in the room, the tem- 
perature of the thermometer will be observed to sink — first 
rapidly, then more slowly. The thermometer cools, 
losing part of its heat to the surroundings. The air in 
immediate contact with the thermometer becomes warmed 
and, expanding thereby ( see 3 ), ascends, yielding its 
place to other portions of air, which in the same manner 
become warmed and are thereby removed ; this diffusion 
of the heat of the thermometer is called convection. 
But the greater part of the heat of the thermometer is 
r a d i a t e d in all directions. 

33. The velocity, v, of cooling isdirectly 
proportional to the excess, e, of tempera- 
ture of the cooling body over the sur- 
rounding; or, if o is a constant quantity, this law of 
cooling may be expressed by 

v=c.e. 
To demonstrate this law, first determine the tempera- 
ture, t, of the surrounding by placing the thermometer 
in the position where it afterward is to cool, and keeping 
the thermometer in this place until it is stationary (neither 
sinks nor rises) ; read the temperature, t, now indicated. 
Then heat the thermometer on the water bath, by placing 
it on the watch glass so as to prevent its getting moist. 
Now remove it to the place occupied before, and accurate- 
ly observe the time at which the sinking column passes 
the successive ( half and full) divisions on the scale. This 
can be best done by t w o students working together, stu- 
dent A counting aloud the beats of a second 
pendulum (Elements of Physics, 39 ),the other student, B, 
observing the sinking column. Student Bhas on a slip of 
paper, entered one below the other, the divisions of the 



12 Chapter L 



6cale above t ; while A counts aloud, B enters the Dum- 
ber, n, called by A when the column exactly passes a 
given division, h, on his paper at the corresponding place. 
Then the observations are entered in the journal of ex- 
periments in the following form : — 

No. 



h D 


i v e 



The first column gives the number of the observ- 
ation made, the second the division or height, h, of the 
column at the number, n, seconds entered in the third 
column. In the fourth column the interval, i, seconds 
is recorded, expressing the time (in seconds) required 
to sink one (or one-half) division (cm). Hence the ve- 
1 o c i t y, v, of cooling is 

v=L 

that is, the number of divisions which the column sinks 
in o n e second. 

By subtracting the temperature, t, of the surroundings 
from each, h, we obtain the e x c e s s, e, in temperature 
of the thermometer over the surrounding, e = h — t. By 
finally dividing each, v by e, you obtain values in the 
last column not differing niuch* from one another. The 
mean of all these values you call c. 

The law of cooling was first demonstrated by New- 
ton. 

34. If the cooling thermometer is placed upon a piece 
of iron or other metal, the velocity of cooling will in- 
crease very much ; if it is packed in cotton contained in 
a paper box, the velocity of cooling will be diminished. 

By such experiments it can readily be proved, that 
metals are good conductors of heat, while woolen 
cloth, hair, and cotton are very poor conductors. 
Wood is also a rather poor conductor ; stone a better con- 

•It is best only to uefe the values e, which are at lea§t from 5 to 10 cm. 



Thermometer and Calorimeter. 13 



ductor than wood, but very much less a conductor than 
the metals. 

Among the metals, silver and copper are found to be 
the best conductors for heat. Iron, lead, and especially 
platinum, are much less perfect conductors. The low con- 
ductibility of platinum contributes very much to make 
it a good support in blow-pipe experiments. 

35. If such a thermometer has one portion of its side 
wall of bright glass, another portion painted with dull 
lampblack, a third coated with gold-leaf; if it furthermore 
during the cooling is packed with cotton in a paper box, 
one side of which has a circular opening somewhat less 
than the above coverings; then it will be found that the 
velocity of cooling is least when the gilt side radiates, 
greatest when the lampblack radiates, and intermediate 
for the glass. 

These observations prove, that lampblack is the best 
radiator, metallic gold the poorest radiator, while 
glass is intermediate. 

In a like manner the radiating power of other substan- 
ces might be determined. 

36. The facts and laws here demonstrated are of very 
general application in common life and in the arts. The 
student should point out a number of such applications. 

III. THERMOMETER AND CALORIMETER. 

37. No two thermometers, such as described in article 
31, will indicate the same number on their scale, although 
put in the same place. They are, therefore, unfit for gen- 
eral use. Besides they are not very susceptible to small 
changes in temperature. 

38. The thermometer now in general use consists of 
a stout glass tube, 5 mm. external diameter, with a very 
narrow flat* hole, figure 5. A cylindrical bulb of com- 

*The hole is flat in order that the mercury filling it may be visible although but 
of a minute volume- The thread or rather ribbon of mercury filling a good ther- 
mometer tube can hardly be seen edgewise, although from the front, it is easilv 
observed. 



14 Chapter I. 



paratively thin walls, but of an external diameter not 
greater than that of the tube, has been blown on one end 
of the tube. The tube and bulb are now completely filled 
with mercury at a high temperature, when the free end of 
the tube is closed by fusion. Upon cooling, the mercury 
column recedes toward the bulb, leaving a vacuum 
above it. (Elements of Physics, 129.) 

If the bulb is inserted in a vessel containing small 
pieces of ice, the mercury column will first sink and then 
remain station ary. The point on the tube at which 
the mercury then remains in melting ice, is marked zero, 
and termed the freezing point of water. 

Thereafter the thermometer is placed in water, and this 
by means of heat brought to boiling. The mercury rises 
with the heating of the water, but remains stationary 
again while the water boils. The point at which the mer- 
cury stands fixed in boiling water is marked 100, and 
called the boiling point.* 

The distance between and 100 is divided into 1U0 
equal parts called degrees Centigrade or Celsi- 
us; the division is carried on above and below, thus 
giving a scale reaching from 30 degrees below zero to 200 
or 300 degrees above zero. Degrees below the freezing 
p unt are usually called negative, and preceded by the 
sign — minus. 

39. Mercury solidifies at about — 40°, so that the mer- 
cury thermometer cannot be used for the determination of 
low degrees of heat'. For this purpose other thermome- 
ters, containing alcohol (usually tinged red to distin- 
guish it from the glass ) are used. 

Mercury boils at about 325°. Hence for the determi- 
nation of high temperatures air thermometers are 
required, i. e., thermometers containing air instead ofmer- 



*In a water bath, the temperature, therefore, never can exceed 100°. See arti- 
cle 19 



Thermometer and Calorimeter \h 



cury. But since air is very much affected by pressure, the 
air thermometer requires intricate calculations on the in- 
fluence of the varying pressure of the atmosphere. 

Two other thermometer scales are much used in the 
arts. Reaumur's scale marks the freezing point 0°, the 
boiling point 80°. On Fahrenheit's scale the freezing 
point is marked 32°, the boiling point 212°. These scales 
are, if necessary, distinguished by adding the in i t i al of 
the name of the inventor to the number of degrees. 

Thus, 50 Q C=40 o R = 122°F. 

In the United States and in Great Britain the Fahren- 
heit scale is in general use in the arts ; on the continent of 
Europe, Reaumur's scale prevails. In science, the Cen- 
tigrade or Celsius scale is very generally used. 
It will be used exclusively in this work. 

40. By performing a c curate determinations of 
volume at different accurately determined temperatures, 
the amount of expansion ( see 3 ) has been deter- 
mined. It has been found that one cubic centimeter of 
the following substances taken at 0° expands by heating 
to 100° to the values given below : 

Air, 1.366. Lead, 1.0084. 

Water, 1.043. Silver, 1.0057. 

Mercury, 1.018. Copper, 1.0051. 

Glass, 1.003. Gold, 1.0045. 

Steel, 1.0036. Iron, 1.0036. 

Platinum, 1.0025. 

If we except the expansion of air, these values of the 
expansion from 0° to 100° are so small, that the methods 
by which these quantities are determined cannot be stud- 
ied in the elements, but must be deferred to the course 
in principles of physical science. 

Here we shall add the curious fact that certain bodies 
con tract, while being heated, at certain temperatures. 
Thus water contracts from 1.0000 to 0.9999 while heated 
from 0° to 4°. It is, therefore, one ten-thousandth more 



10 Chapter I. 



densest 4° than at 0°. Above 4° water expands contin- 
ually while heated. 

41. With a good mercury thermometer the experiment 
on cooling ( 33 ) may be repeated.* The thermometer may 
be inserted in a flask containing a known amount of water, 
or of mercury ; the amount of liquid may be changed, 
and the experiment may be otherwise modified. 

Another even more important experiment for students, 
is the verification of the fixed points ( and 100 ) on the 
thermometer scale. 

The student should also be required to observe the tem- 
perature of the air at given hours of the day during a 
week. 

Great care should always be taken to read the tempera- 
ture correctly and without disturbing the thermometer by 
the heat of the body of the observer. In more refined 
experiments the thermometer is therefore read from a dis- 
tance by means of a telescope. 

42 The thermometer merely measures the degree 
of heat, not the amount of heat. To understand this 
important point, suppose you pour 10 cc. water into a 
small flask and 100 cc. of the same water into a beaker ; 
suppose the water to have the temperature of the room, 
16°. A thermometer inserted into either vessel will there- 
fore indicate the same d e g r„e e of temperature. 

If, now, both vessels are heated on the water bath, then 
after some time the water in both will have reached the 
temperature of say 30. Again the thermometer indicates 
then the same temperature in the beaker and in the flask ; 
the temperature of the water in each was raised 14 de- 
grees, namely from 16 to 30 degrees. 

But it is evident, that it requires more of heat to raise 
100 grams of water 14 degrees, than to raise 10 grams 



*A good thermometer cannot be had except at a cost of several dollars. Hence 
be very careful while handling thermometers. 



Thermometer and Calorimeter 17 

of water this same number of degrees. The a mount 
of heat imparted to the 100 cc, water in the beaker is ev- 
idently 10 times as great as the amount of heat imparted 
to the 10 cc. water in the flask. 

Hence it is evident that the amount of heat 
imparted to a body or taken from a body does not merely 
depend upon the change in temperature of the 
body, but also the weight of the body and even the 
specific nature of the body. Heat, then, must be 
measured in its own unit, the calory. 

43. A calory is the amount of heat re- 
quired to raise the temperature of one 
gram of water, one degree centigrade 
— from 0° to 1°. A kilocalory is 1000 calories, or the 
heat required to raise the temperature of one kilogram 
one degree. 

The term calory is used for the sake of brevity in- 
stead of the phrase unit of amount of heat. In 
practice the word calory is often abreviated thus : c al. 

44. A calorimeter is an apparatus for measur- 
ing the amount of heat in calories. 

In its simplest form the calorimeter consists of a light 
flask ( about 200 cc. capacity ) with a light, sensitive ther- 
mometer, and a known weight, w, grams of water. If 
the temperature of this water rises t° — indicated by the 
thermometer — w times t calories = w. t cal. have been 
imparted to the water. 

For example, to 100 grams of water of 16° in the 
calorimeter add by a 10 cc. pipette 10 grams of water 
of 38° ; shake, and read the temperature of the mixture. 
Tou will find it 18°. 

Hence the 100 gr. in the calorimeter rose 2°, re- 
quiring 200 calories. The 10 gr. added lost 20° in tempe- 
rature, or gave off 10X20 =200 calories, equal to the 
heat imparted to the water in the calorimeter. 
3 



18 Chapter L 



In all cases the amount of heat (in calor- 
ies) imparted to the calorimeter, is equal 
to the amount of heat lost by the heat- 
ing body. 

For this experiment ( and also for 45), it is best to have 
a large amount of water of both temperatures at 
hand in large vessels, so that the temperature does not 
readily change. Then one thermometer io the calorimeter 
is sufficient.* 

45. -But it requires also a certain amount, c, of heat to 
change the temperature of the calorimeter { flask and 
thermometer ) one degree. This value, c, is termed the 
water-value of the calorimeter. 

To determine the same, add a known weight, W, 
grams of water to the w grams of water in the calor- 
imeter. Yery carefully observe the temperature of the 
calorimeter-water, w, the added water, VV, and the tempera- 
ture of the mixture. You will thus find how many de- 
grees, T, the added water was cooled, and how many 
degrees, t, the calorimeter was heated. 

To heat w grams t degrees requires w. t calories. To 
heat the calorimeter of water-valve c grams the same num- 
ber of degrees requires c t cal. additional. Hence the 
calorimeter received wt + ct calories. 

The W grams of water added, lest T degrees, or 
W T cal. Hence we have 

wt + ct=WT 

Frorn^this follows 

c _ 3L W— w 
a8 t the number of grams of water equivalent to the 
calorimeter ( flask and thermometer). 

For actual practice it is well to make W and w 



♦Either transfer by pipette of known volume, or weigh after the reading of the 
Thermometer has been taken. 



Thermometer and Calorimeter . 19 



nearly equal, and to have the hot water only 10 or at 
most 15 degrees warmer than the cold water. See re- 
marks at close of 44. 

46. Calorimeter with chamber. If the mat- 
ter experimented upon cannot be mixed with the water in 
the calorimeter, this apparatus is provided with a chanr 
ber wherein the body is placed while giving off its heat. 

Thus to determine the amount of heat produced by the 
combustion of charcoal the combustible is burnt in 
a metallic chamber surrounded by the^water of a sufficient- 
ly large calorimeter. The amount of water, w, in the 
calorimeter, and the water value, c, of the calorimeter are 
known as well as the change, t, in temperature produced 
by the combustion of a known weight ( n grammes ) of 
charcoal. Then if n grams produce wt + ct cal.>. 
one gram of charcoal produces by its combustion 

w t + c t , 

cal. 

n 

47. In this manner Favre and S i 1 b e r m a n found 
that one gramme of the following substances produces by 
complete combustion the number of calories stated oppo- 
site its name : 



GASES AND, LIQUIDS. 

Hydrogen .... 34,460 cal. 

Marsh gas 13,060 " 

Oleiiant gas 11,860." 

Oil of turpentine.. 10,850 " 

Olive oil 9,860 " 

Ether . . 9,030 " 

Alcohol 8,960 " 

Wood spirits 5,300 " 



SOLIDS. 

Anthracite 8,460 cal. 

Charcoal 8,080 " 

Coal, good 8,000 " 

Tallow 8,000 " 

Coke ...8,000 " 

Wood, dry 4,025 * 

" moist ...3,100 
Phosphorus . . . .5^750 

Sulphur 2,260 

Iron .1,580 " 

Common illuminating gas consists essentially of olefiant 
and marth gas, and produces about 12,000 cah per gram 
by combustion. 



a 



20 Chapter I. 



48. The specific heat, s, of any substance is 
the number of calories required to heat 
one gram of the substance one degree 
centigrade. According to 43 the specific heat of 
water is therefore o n e. For most other substances the 
specific heat is much less than one, especially for the 
heavy metals, like gold, mercury and lead. 

49. To produce a change of t degrees in the tempera- 
ture of a substance of specific heat, s and weight, w, re- 
quires, therefore, s. w. t. calories. 

50- Accordingly the specific heat of a substance not 
affected by water may be determined by immersing a 
known weight of the substance, heated to a known tem- 
perature, into the water of a calorimeter, and carefully 
observing the resulting temperature. 

If, then, the water in the calorimeter, together with the 
water value of the calorimeter, be W grams, the change 
in temperature in the calorimeter be T, the calorimeter 
will have received W. T calories. 

If at the same time the w grams of the substance 
lost t degrees in temperature, the substance gave of s. w. t 
calories to the calorimeter ; see 49. 
Hence W T = s w. t 

from which the specific heat s of the substance 

W. T 

s= - 

w. t 

51. By means of a lead weight or ball of w = 500 
grams, heated i n the water of the water bath to about 
90°, then immersed into a beaker-calorimeter containing 
about 300 grams of water of common temperature, the 
specific heat of lead may be determined by the student. 
About one hundred grams of glass fragments, heated 
in a beaker on the water bath, will also give a good re- 
sult. 

52. Careful experiments of this kind have given for 



Fusing and Boili?uj. 



21 



the following bodies the specific heat given opposite the 
names : 

MINERALS. 

Marble 0.216 cal. 

Calcite 0.205 " 



Siderite 0.182 

Hematite 0.164 

Pyrite 0.130 

Blende 0.115 

JBarite ..0.109 

Galenite 0.053 



Glass 0.198 

Water 1.000 

Air 0.237 



METALS. 

Lead 0.031 cal 

Platinum 0.032 " 

Gold 0.032 " 

Mercury 0.033 " 

Tin 0.056 " 

Silver 0.057 " 

Copper .... ....0.096 " 

Brass 0.094 " 

Zinc 0.096 " 

Iron 0.114 " 



Phosphorus 0.189 

Sulphur 0.203 

Charcoal 0.241 



Accordingly it requires only 33 calories to heat 100 
grams of mercury 10 degrees, while it requires 1000 
calories to heat an equal weight of water the same num- 
ber of degrees. 

IV. FUSING AND BOILING. 

53. The conversion of a solid into a liquid by means 
of heat is termed f u s i o n (see 4, and also Elements of 
Physics, 113 and 151). But not all substances are fusi- 
ble; some are volatized or even decomposed ( see 6 ) by 
heat, without fusing. The change from liquid to solid by 
cooling is termed solidification. 

54- Volatilization is the conversion of a liquid into 
vapor or gas by means of heat. But not all liquids are 
volatile, some decomposing (see 5) by heat without 
volatilization. 

Water, kerosene, and alcohol are volatile liquids; sweet 
oil is a non-volatile liquid. Liquids, which are non-volatile 
are, also, at times, called fixed liquids. 

By cooling, the vapor formed is condensed again to 
a liquid. This change of aggregation is also often called 
1 i q u e f a c t i o n.* 



*The water on the surface of the earth shows all these changes in aggregation on 
a grand scale ( see Cosmos). It evaporates, and as steam forms part of the ai- 



Chapter I. 



55. Yolatization takes place mainly at the surface of 
the liquid ; hence it is accelerated in wide and shallow 
vessels. If a liquid is volatilized intentionally the process 
is also called evaporation. This operation is usually 
performed on the water bath. 

If the liquids yield combustible or obnoxious vapors, 
evaporation lias to be performed with great care in appa- 
ratus specially prepared for this purpose. 

56. K a volatile liquid such as w a t e r is heated in a 
flask on a sand bath, volatilization at the surface will soon 
be accompanied by the formation of small bubbles of 
vapor at the bottom and walls of the flask. These bub- 
bles will ascend, and diminish in size, producing the well- 
known simmering sound. After some further heat- 
ing, the bubbles formed will no longer condense, but rise 
through the liquid, increasing in size as they rise to the 
surface, where they burst. The liquid will at the same 
time be put into a violent commotion by these bub- 
bles. In this state the liquid is said to b o i 1. Hence : 

A liquid boils when vapor is formed 
throughout its entire mass in bubbles, 
which increase in size as they rise 
through the liquid, thereby commoting 
the liquid. 

57. If the vessel be completely closed, the liquid 
will not boil ; vapor will continue to form until the pres- 
sure thereof opens the vessel by explosion. 

It is not even necessary that the vessel should be com- 
pletely closed ; if the opening be insufficient to permit the 
vapor to escape as fast as formed, explosions may also 



inosphere at all times. Upon cooling, a portion of this steam condenses, and 
becomes visible as cl ouds, f og s or dews. Kain is condensed vapor de- 
scending from higher parts of the air. 

Hail, snow, frost, and ice result when the temperature sinks below the 
freezing point. 



Fusing and Boiling. 23 



occur upon continued heating. Examples : accidental 
explosions of steam boilers. 

58. In the process of distillation, boiling and 
liquefaction take place at the same time in different por- 
tions of the apparatus. A distilling apparatus, therefore, 
always consists of two parts, the fl a s k or retort, where- 
in the liquid to be distilled is boiled, aud the co n d e n- 
s er, wherein the vapor formed is liquefied again. 

The heat imparted to the liquid in the flask, to convert 
the liquid into vapor, has to be removed from the vapor in 
the condenser in order to re- convert the vapor into liquid. 
This is usually accomplished by passing a slow current of 
cold water along the tube wherein the vapor escapes from 
the flask. 

If the volatilized substance condenses to the solid 
form, this process is no longer called distillation, but 
sublimation. 

59. A vertical section of a simple distilling apparatus 
for students' use is represented in figure 6. The glass 
flask, A, (from 50 to 100 cc. capacity) is heated on the 
water or sand bath. The condenser consists of a wide 
glass tube, B C, which by a rubber or cork stopper is 
fitted into the flask. The tube, B C, passes first vertically 
upwards, and thereafter slopes gently down, its lower end 
being inserted into or placed above* the receiver, I). 
A tin tube, about three times as wide as B C, encloses 
nearly two-thirds of this tube, which is fitted into the tin 
tube by corks, K K. Narrow glass tubes are fitted by 
means of corks to the tin tube at E and at F. The lower 
glass tube, F, is by means of a rubber-hose siphon con- 
nected with a flask, G-, with water, while the upper glass 
tube, E, is by means of another rubber tube connected 
with the flask H. To regulate the flow of water, an ad- 



♦Students should not distil any dangerous liquids : at least no liquid more volatile 
than alcohol. Otherwise very special precautions are to be taken, which 
it iB tfuperfluouB here to detail. 



24 Chapter L 



justable spring clamp of some kind should be put upon 
the rubber tube from G-. 

The condenser may be further simplified, but it is not 
advisable to do so for actual and frequent use in the 
school laboratory. 

The flow of the condensing water should be so regu- 
lated that the water collecting in H is only 10 or 15 de- 
grees above the temperature of the room. A few pieces 
of ice thrown into G increases the effectiveness of the 
condenser very much. 

60. The operation of distillation is of the utmost im- 
portance, both in the arts and in science ; for b y distil- 
lation we can readily separate the more 
volatile substances from the less vol- 
atile materials. 

Thus we obtain distilled water, free from any of 
the uon- volatile impurities of common well and cistern 
water by distilling the latter — the impurities remaining in 
the still or flask. So alcohol, volatile oils, and many acids 
are manufactured. 

By placing petals of roses in the water of the flask, we 
obtain r o s e-w a t e r, by distillation, possessing the char- 
acteristic odor of the rose. Hence, the odor of the rose is 
due to some volatile substance. 

If the plant contains enough of the volatile substance 
the latter often collects on the water in the receiver, as in 
the case of the light volatile oils." 

Examples for students' laboratory practice are readily 
selected from the preceding. 

*To increase the interest in the operation of distillation, the student may add 
from one to five grammes of some of the following crushed vegetable materials to 
25 to 50 cc. water to be distilled. He will then in all cases have enough of the vol- 
atile oil distilled over, to recognize it. If the oil is lighter than water it will float 
on the surface of the water in the receiver; if it is heavier, it will be found at the 
bottom. Hence we add the specific gravity, G, of the oil to guide the student. 
- It is also important to notice that the boiling point, T, of many volatile oila is 
higher than that of water ; still, in the presence of much steam, these oils are 
carried over with the latter. 



Fusing and Boiling. 25 

61. In case the flask contains a mixture of two liquids 
of different volatility, these liquids may be partially sepa- 
rated by f r a c t i o n a 1 distillation. The first portion 
(fraction) passing into the receiver contains mainly the 
most volatile of the two liquids. The receiver is then 
changed to receive another fraction of the distillate, which 
already will contain more of the less volatile substance. 
In this manner, by several changes of the receiver, small 
fractions of the distillate are separately collected, each 
succeeding fraction being less volatile than the preceding 
one. 

Example: Mixture of alcohol and water, or alcohol 
and glycerine. Determine the specific gravity of the mix- 
ture and of each fraction. 

62- Having now studied the different changes of 
aggregation in a more general manner, we are prepared 
to understand and to demonstrate the laws governing 
these changes. 

The laws of fusion are: 

1. A fusible body fuses at a fixed degree of tempera- 
ture, termed the fusing point. 

2. It requires a fixed amount of heat to convert one 
gram of the solid at the fusing point into a liquid of 
the same temperature ; this amount of heat is the latent 
heat of fusion of that solid. 



The part of the plant used is indicated; also the common and officinal name 
of the plants, as well as the yield of oil in centigrams for one gram of the 
part of plant used: — 

COMMON. OFFICINAL. PABT. W. Gr. T NOTE. 

1. Black mustard. Sinapis nigra. seed. 5 — — very pungent. 

2. Bitter almond. Amygd. amara. kernels. — — — poisonous. 

3. Clove cinnamen. Persea caryophyll. bark. — — — dark brown. 

4. Peppermint. Mentha piperita. herb. 1 0.9 185° 

5. German chamomile. Matricaria chamomilla.flower 7 0.95 — blue. 

6. Cloves. Coryoph. aromat. flower buds. 5 1.04 243° 

7. Black pepper Piper nigra. fruit 2 0.9 — 

The oil is named after the plant from which it ia obtained. Thus " mustard oil, " 
" oil of bitter almonds," etc. 

Of course, only some one of these distillations should be performed by each 
student. 

4 



26 Chapter I. 



The laws of ebullition exactly correspond to the 
preceding, namely : — 

1. In an o p e n vessel a liquid boils at a fixed de- 
gree of temperature, called the boiling point of the 
liquid. 

2. It requires a fixed amount of heat to convert one 
gram of the liquid at the boiling point into vapor 
(gas, steam) of the same temperature. This amount of 
heat is called the latent heat of vaporization 
of that liquid. 

It is apparent that the laws of fusion and ebullition may 
be expressed in one law as follows : 

If by heat the state of aggregation of 
a substance changes, this change takes 
place at a fixed degree of temperature, and 
consumes (or produces) a fixed amount o f 
heat for each gram of the given sub- 
stance. 

It is hardly necessary to state that the heat required to 
change the solid into liquid is again reproduced when 
this liquid changes to solid. So also the heat consumed 
in vaporization is again produced in liquefaction. 

We 6hall now detail the experiments which quantita- 
tively demonstrate the above laws. 

63. A portion of a readily fusible solid, in small frag- 
ments, is heated in a flask or dish on the sand bath. A 
sensitive thermometer, surrounded by the solid, is care- 
fully read at the end of each one or two minutes. The 
results recorded in the journal thus : — 



No. II Time. | Temperature. | Increase. || Remarks. 



In the last column the appearance of the substance is 
recorded. 

It will then be found that the temperature rises quite 
uniformly at first ; that after a while the rise or increase 



Fusing and Boiling. 27 

iu each interval of time becomes smaller ; that finally, 
when the substance commences to melt, the temperature 
ceases to rise. 

These observations should be graphically represented, 
the time as abscissas, the corresponding temperatures as 
ordi nates. ( Compare Elements of Physics, 74). The 
curve drawn through the extremities of the ordinates 
then will be found to rise gradually at first, to remain 
horizontal while the substance melts, and to slowly 
ascend again after all of the substance has been melted. 

Ice is the most convenient example. Stearine, bee's 
wax, sulphur, and fusible alloys of bismuth, lead and tin 
( proportions, 2:1:1) may also be used by the student- 

64. In a like manner observe the gradual heating and 
final ebullition of a liquid ; water or alcohol are most 
suitable for students. 

In the case of water the flask may be open ; but in case 
alcohol is used, it should be heated in a distilling appara- 
tus (59) of sufficient size that a thermometer can be in- 
serted air tight through the cork. The thermometer 
should reach to within about a half centimeter of the bot- 
tom of the flask. 

Record the experiments, represent them by co-ordinates 
precisely as directed above, 63. 

65. But few common substances can be changed 
within moderate temperatures from solids to vapors ; and 
even these few should not be experimented with by the 
student. 

The following table gives the boiling and fusing point 
of some of these substances : 

FUSING POINT. BOILING POINT. 

Mercury —39° 350°. 

Bromine —7° 63°. 

Water 0° 100°. 

Phosphorus 44° 280°. 

Iodine 107° 175°. 

Sulphur 115° 408°. 



28 Chapter I. 



The rise in temperature observed in heating separately 
a small quantity of ice and of iodine is represented by co- 
ordinates ( see 63 ) in figure 7. The full line corres- 
ponds to water, the dotted line to iodine. 

From the above it will appear that the fusing or boiling 
point of any substance is a most important specific 
property of the same, which ought in all cases to be de- 
termined, to form part of the description of the substance. 
Compare El. Phys., 214. 

66. The latent heat of fusion and ol vaporization is 
indicated in the diagrams of 63, 64, and 65 by the 
horizontal position of the curve. Since during the changes 
of state the temperature fails to rise, although heat is con- 
tinually applied, it follows that heat is required to effect 
this change. 

To determine the precise amount of latent heat requires 
careful experimentation with the calorimeter. Here it 
must be sufficient to determine the latent heat of fusion 
for ice and the latent heat of vaporization for water. 

67. The latent heat of water is the number of 
calories required to convert one gram of ice of 0° into 
water of 0°. ( Compare 62.) 

To the water in the calorimeter add from five to ten 
grams of ice in small pieces ( dried between blotting 
paper) for each 100 cc. water in the calorimeter. Care- 
fully ascertain the changes in temperature. 

If the weight of the water (together with water- value 
of calorimeter, see 45) is "W, its change in temperature is 
T, then W T calories have been removed from the calor- 
imeter. 

If w grammes of ice of 0° were taken and fused, the 
fusion required w. 1 calories. The water of 0° resulting 
was warmed to t°, the final temperature in the calorimeter, 
this requires w. t calories. Hence 

W. T — w. 1 + w. t 
or the latent heat of water 

1 T — t 

w 



Fusing and Boiling, 29 

Careful experiments have given 1 = 79.25 cal. 

68. The latent heat of steam is the number 
of calories required to convert one gram of water of 
100° into steam of the same temperature. (Compare 62.) 

Distill about 10 cc. water in the usual manner, but ob. 
serve carefully the temperature of the cooling water, and 
the temperature of the water having served for cooling ; 
suppose it has been heated T degrees. Also determine 
the weight of the cooling water actually used — W grams. 

Thus by the condensation of the w r grams of distilled 
water obtained, W. T calories have been imparted to the 
cooling water. 

If the latent heat of steam is 1, the liquefaction of w 
grammes of steam of 100° to water of 100° yields w 1 
calories. This water is furthermore cooled t degrees, de- 
termined by observing the temperature of the distilled 
water and subtracting this temperature from 100°. By 
this cooling an additional amount of w t calories is given 
to the condensing water. Hence 

W.T=w.t-fwl 
from which 

W 

1 = — • T — t 

w 

About 1,000 grams of cooling water should be used 
for each 10 grams of water distilled. 

The most careful experiments have given 1 — « 537. 

69. The following very striking and highly important 
results have been established by such experiments. (67, 
68):- 

1 gr. ice of 0° -f- 79.25 cal. — 1 gr. water 

1 gr. water of 0° + 100 cal. = 1 gr. water 

1 gr. water of 100° -f 537 cal. = 1 gr. steam 

Accordingly 

1 gr. ice 0° -f 716.25 cal. = 1 gr. steam of 100 c 



of 


0°. 


of 


100°. 


of 


100°. 



30 Chapter 1. 



and also, 1 gr. steam of 100° — 716.25 cal. = 1 gr. ice 
of 0°. 

It will be seen that the mere change from solid to liquid 
requires for water as much heat as to raise the tempera- 
ture of water of common temperature to the boiling 
point. . To change boiling water to steam requires nearly 
seven times as much heat ! 

Again, one gram of steam condensed to water of 20° 
yields 617 calories, or as much of heat as 617 grams of 
water cooled one degree! 

Upon these facts rest the applicability of steam for 
heating purposes and the enormous consumption 
of fuel* for the production of steam. 

70. A multitude of common phenomena can be ex- 
plained by the laws demonstrated in the preceding. The 
action of freezing mixtures (Elements of Physics, 113, 
note ) ; the cooling e ff e c t of an}' evaporating liquid ; the 

*The following practical facts' will prove of interest : — 

The proper temperature of a room for occupation by man is 15°. Each full grown 
healthy person requires about 10 cubic meters fresh air per hour ; and gives off 
(above the heat consumed in his perspiration ) about 45 kilocalories ( kgr. degrees ) 
per hour. If now the air outside the room is t degrees below 15°, a number n per- 
sons in the room require 

w' = 3 n ( f— 15 ) 
kilocalories per hour, as you will readily calculate from the above data in connec- 
tion with 52 and Elements of Physics, 33. 

To compensate for the cooling effect (admission of cold air, etc.,) of the outer 
walls, requires 

W" = F. t 
kilocalories per hour, if the surface of the outer walls be F square meters ( window 
surface counted twice). 

Hence, a hall to hold n persons requires ot heat per hour kilocalories ; 
W = w' plus w" = Ft plus 3n ( t — 15 ) 

Since one kilogram steam on the average yields 550 kilocalories by condensa- 
tion and cooling, this room will require s == 0.00182 w kgr. steam per hour, and 
0.0012 w square meters of steam pipe surface, if the room is to be heated by steam. 
To produce this amount of steam requires in practice about one-seventh of coal, or 
0.0002C .w kgr. coal per hour, and a heating surface in the steam boiler of 0.000125 
times w square meters. 

By means of these data ( from Weisbach) you can readily solve the principal 
questions in regard to the heating of rooms and buildings by steam. 

The area, V, (in square meters)'of the opening of the ventilator, the height of which 
is h meters, should be 

to allow 10 cubic meters of fresh air per hour for each person. 



Fusing and Boiling. 31 



solidification of carbon bisulphide* by violently blowing 
upon a small portion contained in a watch glass — are a few 
characteristic instances to test the student's sagacity. The 
teacher may add other instances of a like nature. Also 
solve some practical problems on heating by steam, using 
the data given in the foot note to 69. 

71. In the preceding the boiling liquid was supposed 
to be in an open vessel, hence under the common pres 
sure of the atmosphere ( 76 cm., see Elements of Physics, 
130). The laws of ebullition remain essentially the same 
if the pressure on the liquid changes; except that the 
boiling point rises and sinks with the 
pressure on the surface of the liquid. 

Thus water does boil at 83° if the pressure on its sur- 
face is diminished to one-half (38 cm. ) ; it boils already at 
50° if the pressure is diminished to one-tenth ( 7.6 cm. ), 
while it does not boil until heated till 144° if the pressure 
is four times as great as usual, (304 cm.). 

72. The pressure, p, of vapors corresponding to any 
temperature, t, has been carefully determined for different 
liquids by experiments with the apparatus represented in 
figure 8. 

In the strong boiler, B, the liquid is heated. The tem- 
perature of the liquid is determined by the thermometer, 
t, immersed in the mercury contained in a narrow iron 
tube. A strong tube, D, passes from the boiler to a closed 
cistern, C, with mercury. A vertical glass tube, A, open at 
both ends, passes through the cover of C into the mer- 
cury. 

When the thermometer, t, in B, remains stationary, the 
level of the mercury in A measures the pressure, p, of the 
vapors corresponding to that temperature, t. In this 
manner the following results have been obtained, the pres- 



*If the teacher wishes to perform this really striking experiment, he should bear 
in mind the great combustibility and the offensive odor of this substance. Exhib- 
it the experiment immediately before dismissing the class. 



32 



Chapter L 



sure being expressed in centimeters c 
Elements of Physics, 121): — 


f mercury. 


( See 


t 


20° 


0° 


20o 


40 


60° 


80 


100 


Mercury. 




0.002 


0.004 


0.008 


0.02 


0.04 


0.07 


Water. 


0.1 


05 


1.7 


5.5 


14.9 


35.5 


76.0 


Alcohol. 


0.3 


i 

1.3 4.5 

l 
i 


13.4 


35.1 


81.3 


169.5 


Ether. 


6.8 


18.3 


43.3 


91.0 


172.9 


302.4 


495.1 



It will be noticed that the pressure increases at a much 
more rapid rate than the temperature. The same is ap- 
parent from the following table for steam of water above 
100°. The pressure is given in atmospheres of 76 
cm. mercury each. (Elements Physics, 130 ) : — 



Pressure. 



10 15 20 



temperature. 100.0 120.6 133.9 1 144.0 152.2 159.2 165.3 170.8 175.8 180.3 198.8 213.6 



Kise for each new 
atmosphere. 



20.6 



10.1 8.2 7.0 



6.1 



5.5 



4.5 



These values are represented in figure 9. The tempe- 
rature as abscissas (scale 50 degrees to the centimeter), 
the corresponding pressure as ordinates (2 atmospheres to 
the centimeter). 

For these higher temperatures, t, (above 100°) the pres- 
sure, p, per square centimeter is nearly 

kilograms. This formuala gives for t = 200° a pres- 
sure of 16 kilograms ; direct observation has given 
5.89 kilograms. 



CHAPTER II. 



HEAT AND MECHANICAL WORK. 



73. Very much of the mechanical work accomplished 
in civilized countries is performed by steam power. 
By the use of steam the population of these countries, in 
regard to absolute mechanical power and production, is 
virtually greatly increased. Besides, a comparatively 
larger percentage of the actual population, by this steam 
power, becomes released from muscular labor, and is per- 
mitted to cultivate their intellectual powers. Thus, the 
steam power is in every respect one of the principal pil- 
lars of modern civilization. 

This is, however, not the place for an elaboration of 
these views ; nor can we here give detailed descriptions of 
steam engines. In these elements of physical science, it 
would be improper to go beyond the fundamental princi- 
ples upon which the application of steam power depends. 
Hence we shall say nothing about those parts of the steam 
engine, which serve to transmit the power to the various 
machines to be moved ; we shall only refer to the two 
most essential parts of every steam motor, namely the 
boiler and the cylinder. 

74. The combustion of fuel under the boiler 
converts the water in the boiler into steam. 

To convert one gram of water of 0° into steam of 
100° requires (see 68 and 69) 637 calories. If the steam 
is to be heated more, in order to possess a higher pressure 
(see 72), it requires about 0.3 calories more for each addi- 
tional degree in temperature (Regnault). Since in com- 
mon practice the water used is of a temperature of from 
5 



34 Chapter II 



10° to 20°, we may say, that about 648 calories' are 
sufficient to convert one gram of the 
water used, into steam commonly ap- 
plied. 

But 1 gram of good coal produces by complete com- 
bustion, 8,000 calories ; hence, if completely util- 
ized, one gram of good coal would convert 12-J 
grams of water into steam under usual circumstances. 
In other words, 1 gram of water would require but 0.08 
grams of good coal to be converted into steam. 

Therefore, to convert S kilograms of water into 
steam would require only 

C = 0.08 S 
kilograms of good coal, if the same could be completely 
utilized. 

In practice, much of the heat is wasted — some necessa- 
rily, in order to produce the draft in the chimney, etc. 
Hence, twice the above amount of coal is used, or in prac- 
tice* 

C = 0.16. S 
' The heating surface, F, of the boiler, B, required to pro. 

duce, S, kilograms of steam per second is 
F = 150. S square meters. 
75. The steam produced in the boiler passes through 
a wide tube, n, to the steam cylinder, C, figure 10. 
In this cylinder a p i s t o n, M, fits steam tight, and is 
pushed alternately up and down the cylinder, by the^steam 
being admitted alternately at the bottom (through 2) and 
at the top (through 1) of fthe* cylinder.f The piston- 
r o d, r, is connected|with the^ machinery to which the 
motion produced is to be communicated. 

*Redtenbacher gives 0.15. 

fThe valve che s t, ch, contains ajhollow s li de, m, the cavity of which com- 
municates with the^air or with the condenser. (See 76. ) In the position of the slide 
shown in the figure, the piston is forced upwards, C communicating with n, and c 
with m ; hence the piston is forced down.;. When down, the .slide is pushed down 
again, whereby the piston moves up'as shown above. * In 'this [manner the steam is 
admitted alternately above and below the piston. 



Heat and Mechanical Work. 35 



The details of construction vary exceedingly in differ- 
ent machines ; they are described in special treatises on 
the steam engine. Here it >must be sufficient to show how 
the nominal power of the engine can be calculated 
from the diameter, d, (centimeters) of the piston, the length 
s, of the stroke (in meters), the number, n, of strokes per 
second, and the pressure, p, in the cylinder ( in kilo- 
grams per square centimeter). If the area of the piston 
is a square centimeters, the total pressure on the piston is 
a.p kilograms. 

Hence the mechanical work of each stroke is s.a.p 
kilogrammeters. ( See El. of Phys., 84) ; and in 
each second ( n strokes ) the work will be n. s.a.p kgr. M, 
or (according to Elements of Physics, 85) 

N _ n - 8 « a - P 



75 
horse power. 

Since a = — * d2 (Elements of Physics, 48), the above 

number of horse powers is also very nearly 

n. s. p. d 2 
100 

The pressure in the cylinder is about f of the pressure 
in the boiler, which latter pressure is indicated by proper 
gauges. 

76. While the steam is admitted to one side of the 
piston, the steam in the cylinder on the other side of 
the piston is permitted to escape through the slide, m, (fig. 
10). 

In High Pressure engines this steam escapes 
into the atmosphere ; but in doing so it has to overcome 
the pressure of the atmosphere, thus reducing the effect- 
ive pressure one unit. In order that such machines can 
work to advantage, the pressure of steam in their boiler 



36 Chapter II. 



must therefore be rather high ; it is usually about 6 or 7 
atmospheres. 

In Low Pressure engines, m connects with 
a condenser, that is, a large reservoir wherein cold 
water is constantly injected. The steam is thereby 
condensed, and on the corresponding side of the piston 
hardly any pressure is left. Such machines can therefore 
work even with one atmosphere pressure in the boiler, 
hence their name. 

The principal advantage of the condenser consists in 
the recovery of some of the latent heat of the steam. The 
water, warmed thereby in the condenser, is pumped into 
the boiler, thus saving fuel. But the condenser makes the 
machine also more cumbrous, and cannot be used at all on 
locomobiles. 

77. It is not necessary that steam be admitted to the 
cylinder during the entire stroke. After about one- 
third of the stroke, when therefore the cylinder is -J- 
filled with high pressure steam, the steam may be c u t o if 
from the boiler ; the great pressure will continue to carry 
the piston on, while the steam back of it expands from 
i cylinder till it fills the entire cylinder. Machines pro- 
vided with such cut off are termed Expansion Ma- 
chines. They save much steam, and also economize 
heat, because during expansion the steam partially lique- 
fies in the cylinder ; the latent heat thus resulting in- 
creases the effect of the steam remaining uncondensed 
under the piston. 

High pressure engines are usually without condenser 
and without expansion ; they require about one kilogram 
of steam per second for every 150 horsepower. Low 
pressure engines have usually both expansion and con- 
denser ; they work at times as many as 250 horsepower 
by one kilogram of steam per second. 

78. In order to become acquainted with the relation 
of the various rules and laws here given, the student 
should solve the following problem : — 



Heat and Mechanical Work. 37 



An express train is to be moved with a velocity of 15 
meters per second ( about 54 kilometers or 35 miles an 
hour ) on a good railway, which for this velocity gives the 
coeficientof 0.01. (See Elements of Physics 102). The loco- 
motive with tender weighs 20 tons ( of 1,000 kgs each), 
the balance of the train weighs SO tons. 

Required to find how many horsepowers the loco- 
motive must have; how great the diameter of each of its 
two equal steam cylinders, if each piston is to make 2 
strokes of 0.63 meters per second ; also, how much water 
and coal will be required per second and per hour. The 
locomotive has of course a high pressure engine without 
expansion and without condenser, using steam of from 6 
to 7 atmospheres pressure. 

Besides solving problems like the above, the students 
should visit good steam engines and carefully observe the 
same both while at rest and while in activity. 

79. The steam engine constitutes a most striking dem- 
onstration of the fact that heat produces mechan- 
ical work. As shown in the preceding, hundreds of 
horsepower are performed by the heat resulting from 
combustion under the boiler of a single steam engine. 
Thus we may well ask, how much of mechanical work is 
produced by the expenditure of one kilocalory? How 
much c a n be produced ! 

Again, it is a matter of quite common observation, that 
mechanical work produces heat. The ham- 
mering of a piece of lead makes it warm; rubbing two 
pieces of wood produces fire ; stopping a train by the 
brakes makes the sparks fly ; and in the dressing of cast- 
ings of iron by means of rapidfy revolving wheels, the 
sparks form a continuous and beautiful shower. Hence 
the question also turns up, how many calories are pro- 
duced by one dynamo ? 

80- R. Mayer of Heilbronn, in 1842, first solved 
both of these questions in an unmistakable manner ; Joule 



38 Chapter II 



of Scotland, and C o 1 d i n g, of Denmark, demonstrated 
the results of Mayer experimentally. Already C a rn o t, 
of France, in 1824, showed that the mechanical work of 
the steam engine is intimately related to the heat expended; 
while Rumford in Bavaria (but a native of the United 
States), already at the beginning of this century proved 
experimentally that the expenditure of a certain amount 
of mechanical work produced a certain amount of heat. 

As the great result of numerous experimental re- 
searches performed in the most different manner by differ- 
ent experimenters, it appears that mechanical work and 
heat may be transformed one into the other accord- 
ing to the following simple law : — 

One calory is equivalent to 4 2 5 dy- 
namos; and inversely, one dynamo is 

equivalent t o— — -= 0.0024 calories. 
u 425 

Hence one kilogram-degree can produce 425 
kilogram-meters of mechanical work. The latter quantity 
is often termed the mechanical equivalent of 
heat. 

Asa necessary conclusion the mechanical the- 
ory of heat results, according to which heat i s a 
vibratory motion oft he particles. 

81. The most accurate determinations of the mechan- 
ical equivalent of heat have been made by Joule, be- 
ginning as early as 1843, independent of other investiga- 
tors. 

He used a calorimeter, B, figure 11, containing a known 
amount of water, w, and of a known water, value, c; com- 
pare 45. In this calorimeter a paddle wheel (indicated by 
dotted lines in the figure) moves between four fixed metal- 
lic partitions, leaving but a little more space than required 
for the paddles to pass; hence, when the paddle wheel is 
revolved by rotation of its vertical axis, A, the water in 
the calorimeter is violently agitated (as in a churn). 



Heat and Mechanical Work. 39 



The rotation of the paddle wheel is produced by the 
sinking of a known weight, W, attached to the axis in the 
manner shown by the figure. 

Joule now carefully observes the temperature of the 
water before and after the sinking of the weight; 
thus. he obtains the rise, t, in temperature produced by 
the motion. Hence the number of calories (w + c) t 
produced is determined. 

Knowing the weight, W, and the height, h, through 
which it descends, he has W. h, the number of dynamos 
expended. 

Hence if x, the number of dynamos required to pro- 
duce one calory, \yq have 

W.h = x.(w -f c) t 
where all quantities are directly observed, except x. 

From his experiment, Joule found in 1849 the mean 
772 foot pounds English, for one pound-degree, Fahren- 
heit ; which corresponds to 425 kilogram-meters to 
one kilocalory, as above stated. 

By other experiments it has been proved, that the ex- 
penditure of one calory again reproduces 425 dynomos. 
Hence heat and mechanical work are equivalent in 
the proportions stated in 80. 

82. Accordingly, if any number, C, of kilocalories are 
completely converted into mechanical work, W 
(kilogram-meters), we have 

W = 425. C A. 

Inversely, if any given amount, W, of work be com- 
pletely converted into heat, C, we shall have 

W 

C= 4"25 = °-° 024 - W B ' 

By these formulse, expressed in words in 80, we can 
always reduce work to heat* or heat to work. 



♦Heat is accordingly but work accomplished internally, in moving and disturbing 
the particles. 



40 Chapter II. 



83. By these equations, demonstrated by experiment, 
(81), we may test the efficiency of the steam engine in the 
following manner : 

One kilogram of good coal does produce 8,000 kilocalo- 
rise by combustion (see 47). Hence the combustion of 
one kilogram of good coal ought to produce 425 X 8,000, 
== 3,i00,000 kilogram-meters of mechanical work. (See 
82). Now, a horse power continued for one hour repre- 
sents 75 . 60 . 60 = 270,000 kilogram-meters of work. 
Hence the combustion of one kilogram of good coal per 
hour should produce 12f horse power during that hour. 

To keep a steam engine of K horse powers in full activ- 
ity during one hour, ought, therefore, to require a con- 
sumption of about 0.08 1ST kilograms of good coal. 

But if really good steam engines, such as used in actual 
practice, are carefully tested, it is found ( by H i r n ) that 
they use about 8 times as much of coal, or about 0.64 
N for !N" horse powers. At times the consumption of coal 
rises to 10 times the above theoretical amount ; in machines 
kept exceedingly well, and being well constructed, the 
amount has been found as low as 6 times the theoret- 
ical amount, or only about -J N. kilograms. 

Accordingly there is still much room for the improve- 
ment of the steam engine. For an engine using 6 times 
as much as is theoretically sufficient, returns only one- 
sixth or 16f per centum, wasting 83^ per cent; 
and this is the waste of the best steam engines ; while a 
machine using 10 times the necessary amount of fuel, ren- 
ders only one-tenth the full amount of duty — that is, it 
gives 10 per centum of useful effect against 90 per centum 
of waste, El. Phys., 88. 

In fact, a machine which consumes one 
kilogram of good coal per horsepower 
per hour is really a very good ma- 
chine, as now made. But 1.00 kgr. is more than 12 
times the theoretical 0.08 sufficient to produce this power! 



Heat and Mechanical Work. 41 



Such a good machine hardly yields 8 per cent, wasting 
fully 92 per cent of the fuel burnt ! 

84, In view of these strange facts it may well be ask- 
ed, why are steam engines used if they are s o wasteful ? 

The reply is: the low price of coal. Even at such enor- 
mous wastes, the power obtained by burning coal under 
the steam boiler is exceedingly cheap when compared to 
the cost of an equal power produced by muscular effort of 
beasts — and still more cheap if compared to the price of 
human muscular effort. 

Nevertheless, the above results of the scientific test of 
the steam engine are of the utmost importance, because 
they open to the scientific inventor a great field of useful 
labor. 

The construction of the muscular frame as a ma- 
chine, is certainly not better than that of the steam 
engine for work. As to actual cost, there is, as already 
stated, no comparison. The following may show this fact 
in detail : 

The mechanical work (external) of one man per day is 
about 100,000 kilogram-meters. But one kilogram good 
coal burnt, yields, theoretically, 3,400,000 kilogram- 
meters ; that is, one kilogram of coal is, the- 
oretically, equivalent to one day's 
work of 34 men. In average steam engines 12 
times the theoretical amount of coal is consumed ; hence, 
the combustion of one kilogram of good coal under the 
boiler of a steam engine of average quality is equivalent 
to the mechanical labor of 3 men during one day. Ac- 
cordingly, so long as the day's wages of one man exceed 
the price of £ of a kilogram of good coal, so long will the 
steam power of average machines be cheaper than the 
mechanical power of the muscles of man. But, to ob- 
tain even this result, the three men consume m ore than 
three kilograms of food ! 

Besides, the steam engine is infinitely more compact 



42 Chapter II 



than any other : in a comparatively small space it per- 
forms an immense amount of work. Even if men or 
beasts could work with the speed of the locomotive of 
200 horse power, the system of platform wagons holding 
the necessary number of men or beasts would introduce 
friction enough to leave but little for actual pull on a train. 
How many men's service, at 100,000 kilogram-meters per 
day's work, would be required to substitute the day's work 
of a locomotive of 200 horse power? By answering this 
question the compactness of the steam engine will need no 
further demonstration, see 78 and El. Phys., 86. 

85. By the formula, A, in 82, we can readily calculate 
the amount of work, in gram -meters which the 
combustion of one gram of the substances enu- 
merated in 47 can perform, if the heat were completely 
utilized. 

Of course, the combustion of one kilogram produces 
the same number of kilogram-meters here given : 



GASES AND LIQUIDS. 

Hydrogen 14,645,500 

Olefiant gas 5,877,000 

Olive oil 4,437,005 

Ether 4,063,000 

Alcohol 4,032,000 

Wood spirits.... 2,385,000 



SOLIDS. 

Anthracite 3,807,000 

Charcoal 3,636,000 

Coal, good 3,600,000 

Coke 3,600,000 

Wood, drv 1,801,000 

" moist 1,395,000 



The amount of mechanical work which can be per- 
formed by the process of combustion is therefore really 
immense. The combustion of one kilogram of hydrogen 
would lift a million kilograms 14.6 meters high ! The 
combustion of one kilogram of coal would lift one hundred 
tons of coal 36 meters high ! 

86. In the same manner we may consider the different 
states of aggregation of the same substance as differing in 
a certain, fixed amount of mechanical work. For exam- 
ple, the states of water, the thermal differences of which 
are given in 69, become by the mechanical equivalent of 
heat : 



Heat and Mechanical Work. 43 



1 gr. ice of 0° + 35,665 dyn. = 1 gr. water of 0°. 

1 gr. water of 0° + 42,500 dyn. == 1 gr. water of 100°. 

1 gr. water' of 100° +229,225 dyn. = 1 gr. steam of 100°. 

and therefore also 

1 gr. ice of 0°+307,390 dyn. = 1 gr. steam of 100°. 

and also, 

1 gr. steam of 100°— 307,390 dyn. = 1 gr. ice of °0. 

The d y n a m o (El. Phys. 84) here used is one grain 
lifted one meter, or the gram-meter, because the unit of 
weight here used is the gram. The same figures also give 
the commercial values, by inserting kilogram instead of 
gram, when the dynamo also will be the kilogram-meter 
and the calories become kilo-calories. 

87. Water lifted up to a height is still water, but by 
sinking it will again expend the work done in lifting it up- 
(Compare El. Phys., 98, 99, 100.) Thus we have also : 

1 gr. water at the level of the sea + 100 dyn. = 1 gr. 
water at the level 100 meters. 
Inversely, 

1 gr. water at 100 meters above the surface of the 
earth — 100 dyn. = 1 gr. water a t the surtace of the 
earth. 

These relations are apparently similar to those in 86. 
"We may therefore properly speak of the different 
states of aggregation as occupying 
different mechanical levels. The solid state 
is the lowest, the liquid intermediate, the gaseous highest. 

88. In each state of the substance the mechanical level 
may be gradually changed by slowly raising its tempera- 
ture ; suddenly, however, when its state of aggregation 
is raised. Hence the numerical values in 86 are repre- 
sented graphically by figure 12, drawn to the scale of 10,- 
000 gram-meters to one millimeter. The drawing repre- 
sents a terrace, the steep, precipitous banks corres- 
ponding to sudden changes in the state of aggrega- 
tion, while the gentle slopes represent the substance i n 
the different states. 



44 Chapter IT. 



Just as the water flowing down a hill or a precipice, 
sets free an amount of mechanical work proportional to 
the descent, so all materials in cooling may be made to 
perform mechanical work in amount proportional to this 
cooling; but at certain temperatures, a further cooling is 
accompanied with a change in state of aggregation exactly 
corresponding in mechanical work to a precipice in the flow 
of water. 

89. Inversely, by using formula B, of 82, we can cal- 
culate the amount of heat equivalent to any given amount 
of work. 

Thus, the external work of one man is (EL Phys., 86) 
about 100,000 kilogram-meters per day. But this is equiv- 
alent to 2,400 kilogram-degrees, which result from the 
combustion of 0.267 kilograms of alcohol, or from the 
combustion of 0.069 kilograms of hydrogen. (See 47.) 

So also, if a cataract carries 100 litres of water per sees 
ond down a precipice of 100 meters, the 10,000 kilogram- 
meters produced are equivalent to 240 kilogram-degree, 
and will raise the temperature of the water 2.4 degrees, 
provided there be no motion in the water below the fall. 
The presence of the surf, and especially of spray, will di- 
minish this rise in temperature.* 

90. By reference to the concluding articles of the Ele- 
ments of Physics we now see, how heat takes its place 
in the complete circuit of physical agencies which are pro- 
duced one by the other in the most different manner, but 
always in equivalent amounts. Just as impossible as it is 
to produce a particle of matter, except by an equivalent por- 
tion of already existing matter, so impossible it is to pro- 
duce any of the physical agencies — light, heat (including 
combustion), electricity, magnetism, mechanical transloca- 
tion (work), except by an interchange in equivalent pro- 
portion. 

*The water of the Niagara is colder below than above the falls, on account of 
spray, surf, and evaporation. 



Heat and Mechanical Work. 45 

Accordingly, physical science considers all these agen- 
cies as the same in kind, which we call displacement, 
locomotion. The apparently more subtle agencies are 
various states of motion and displacement of the parti- 
cles of matter — motions discerned by reason's eye, 
armed by modern science ; in the coarser agencies of run- 
ning water or sinking weights, we have the joint motion of 
all particles as one, visible to the bodily eye and familiar 
to us from our earliest childhood. 



CHAPTER III 



DISSOCIATION AND ELECTROLYSIS. 



91. When a few small crystals of blue vitriol are 
gently heated in a dry, narrow glass tube ( or in a watch 
glass, heated on a sand bath) they turn into a white 
powder, while the colder parts of the tube are coated 
with drops of water. Blue vitriol, by heat, thus is broken 
up into water and a white substance. If to this latter 
(after it is cooled) a few drops of water are added, the 
white color is again changed to the original blue, and 
much heat is involved during this change. 

92. This action of heat is different from both fusion 
and volatilization ; it is termed dissociation, because 
the one given substance (blue vitriol) was separated, 
decomposed into water and the white powder. 

The white powder which remains is termed copper 
sulphate.* Hence blue vitriol consists of copper sul- 
phate and water. Substances which contain water are 
termed h y d r a t e d. Therefore, blue vitriol is also called 
hydrated copper sulphate. The water in the 
blue vitriol is essential to the crystal form of the latter ; 
for the expulsion of the water also destroyed the crystal 
form. Such water is often termed water of crys- 
tallization, and it can always be expelled by proper 
heating. 

93. All crystallized substances which contain water of 
crystallization, may therefore be dissociated; that is, 



*For it ean be obtained from copper and sulphuric acid, as shown in a subsequent 
chapter. 



Dissociation and Electrolysis. 47 



they can be decomposed by heat alone. 
The water of crystallization will be expelled, and a residue 
free from water (i. e., anhydrous) will remain. 

The amount, w, of the water of 
crystallization in one gram of crystals, 
is determined by carefully heating from £ to 1 
gram of rather small crystals in a watch glass on a 
sand bath until it ceases to loose in weight. You weigh 
the watch glass alone ( = a), with the crystals on (= b), 

b c 

and with the residue* (=c) ; then w = r — grams. 

d — a 

Blue vitriol is by far the best example for prac- 
tice. Green vitriol, white vitriol, alum, and any of the 
Haueroids (El. Fhys., 194 and 195) may also be used, and 
the amount, w, of water of crystallization determined as 
above. Among the minerals, gypsum, is the most 
proper example. 

Some of the above crystals — especially alumf — first 
apparently fu se when heated, but only while yielding 
water; when all the water has been expelled, the white 
residue remains solid and is infusible. The fusion in the 
water of crystallization is termed aqueous fusion. 
The true fusion is distinguished as igneous fusion. 

94. At a moderate heat on the sand bath blue vitriol 
dissociates into white copper sulphate and water (91 to 93). 
But if pulverized blue vitriol is heated on a small platinum 
dish or porcelain capsule, directly* over the flame, so as 



♦Do i.ot weigh until cold. When white, you stop heating. 

fBorax also contains much water of crystallization, which is expelled in making 
a borax bead. (See 27]. If you weigh the platinum wire = w, also weigh off about 
one decigram of borax, = b, on a small piece of paper, and carefully make the bead 

without losing borax, you will find the bead on the wire to weigh about w plus — , so 

that about one-half of the borax is water of crystallization. Careful experiments 
give 47 per cent, of water and 53 per cent, of anhydrous matter. 

♦Supported on a platinum triangle, or iron-wire triangle whereof the wires are 
partly covered by pipe stems. 



48 Chapter III 



to be exposed to a red heat, it will rapidly turn white (by 
the above dissociation ) and continue to change in color 
through brown to bl ack. The black substance remain- 
ing is called black copper oxide, for reasons which 
will be given in a subsequent chapter (IV.) ; here it may 
suffice to state, that the same black substance is obtained by 
heating copper in a flame. The amount of copper oxide 
in blue vitriol may be determined by weighing the 
dish (= a), the same with blue vitriol (= b), and with the 

black oxide (== c) ; it will then be r- — grams in one gram 

d — a 

95- By merely heating the black copper oxide it has 
not yet been further dissociated. However, it is not 
doubted that exposure to a sufficiently high temperature 
will dissociate it again, leaving metallic copper ; but, as 
stated, this dissociation has, so far, never been accomplish- 
ed. 

If we assist the dissociating action of heat by the reduc- 
ing flame of the blow-pipe while the oxide is supported on 
the charcoal, (see 25), we can readily decompose the oxide, 
which thus yields metallic copper.* 

96. But neither by simple dissociation nor by any 
auxilliary to heat, has copper ever been dissociated or de- 
composed in any way. It is, therefore, so far as we are 
able at present to ascertain, a simple sub- 
stance, or a chemical element. 

The following is the most correct definition of this term : 



*A still more simple reduction to the metallic state is the following; 

A small fragment of silver nitrate — one centigram is quite sufficient — is placed 
upon charcoal and the blow-pipe flame directed to a spot near the nitrate. When 
this spot of coal begins to glow, the nitrate suddenly spreads over the red hot 
charcoal, burning the latter violently fdefl agrati o n ], and leaving a white resi- 
due of silver, which exhibits most beautifully the fibrous structure of the wood of 
which the charcoal was made. By removing the silver spot with the penknife a very 
fine object for the microscope will be secured. 

By pressing the silver with the knife, it is burnished. It may also be fused to a 
globule on charcoal. 



Dissociation and Electrolysis. 49 



A chemical ELEMENT is a substance 
which has not yet been decomposed; nei- 
ther by heat alone (dissociation) nor by heat aided in any 
manner whatever. 

A chemical COMPOUND is a homoge- 
neous' substance which can be dissoci- 
ated or decomposed. 

A mixture is a substance which is 
not homogeneous; it can usually be separated by 
mechanical means into several elements or chemical 
compounds. 

It is not necessary to give additional examples here, be- 
cause these terms will gradually become more thoroughly 
understood by the frequent examples in the following. 

97. The principal difference between compound- 
and mixture may be expressed in the following two, 
statements : 

1. Chemieal compounds contain their eo,n- 
stituent components in fixed proportions* mix- 
tures may be made in any proportion. 

2. A chemical compound differs from the sum of its 
constituent components by a certain amount of heat or 
mechanical work; a mixture does not differ m this man- 
ner. 

Thus, in the above example of blue vitriol, we shall find 
a fixed amount of white copper sulphate, and $ fixed 
amount of copper oxide by dissociation. One gram of 
blue vitriol leaves always 0.64 grams of copper sulphate 
and finally 0.32 grams of black copper oxide ; which lat- 
ter before the blow-pipe (95) always yields. Q.25 grams of 
metallic copper.* 

So, also, blue vitriol is Bot sjmply the sum of , copper 
sulphate and water, but less thai* this sum by a con-. 



*The blue vitriol should be mixed; with about tvrkt) its weight* of sodium carbon- 
ate if the experimenter is to succeed ; it is rather to* difficult. f|Qr t&fi beginner. 

7 



50 Chapter III. 



siderable amount of heat (or of mechanical work, see 82). 
That is : 

Copper sulphate + water = blue vitriol + heat. 
The amount of this heat may be determined by the ca- 
lorimeter (44). We shall soon see that combustion is the 
combination of the combustible with oxygen ; hence all 
the examples given in 47 and in 85 may now be 
referred to as demonstrations of the second of the above 
statements. 

98. As a rule, direct combination yields heat, and 
direct decomposition requires heat. That is, if A 
and B are substances, then if they can be combined di- 
rectly to the compound A B, without any intermediate 
agency, we shall have in synthesis or direct com- 
bination : 

A + B = AB + heat, 

and in analysis or decomposition : 

AB + heat = A + B. 

Thus the fuel = A, combining directly with the oxygen 
(of the air) = B, given the product of combustion AB and 
heat; to reproduce the fuel, A, and the oxygen, B, from 
this product of combustion, AB, would require the ex- 
penditure of an amount of heat equal to that 
produced in the combustion. Compare 85 and 47. 

These general results will be further utilized when we 
shall have become familiar with a sufficient number of 
additional facts. 

99. Mercuric oxide* is also readily dissociated 
by gently heating about half a decigram thereof in a small 
dry, test tube. The latter should be held obliquely so that 
the Hame plays on the spot where the oxide lies. The 
oxide quickly turns deep brownish red, and soon has en- 
tirely disappeared. But it has not volatilized ( see 
54 ) : it has dissociated into metallic mercury and 
gaseous oxygen! 

♦Commouly called red oxide of mercury. 



Dissociation and Electrolysis. 51 



The metallic mercury will be seen forming a beautiful 
mirror around the colder parts of the tube, the mirror be- 
ing composed of minute globules of metallic mercury. 

That a peculiar gas has been given off at the same time, 
will be recognized by bringing the glowing point 
of a small splinter of dry pine wood down into the tube;* 
the splinter will begin to burn with great vivacity. 

The gas thus formed and characterized by its energetic- 
ally supporting combustion is called oxygen. It has, so 
far, proved to be an element. See 96. 

100. The teacher may collect a greater quantity of 
oxygen over water (see El. Phys., 127) by heating a larger 
amount of mercuric oxidef in a glass flask connected with 
the gas receiver by means of a rubber tube. He may then 
also exhibit the fact that oxygen most energetic- 
al ly supports combustion by some of the 
most beautiful chemical experiments, such as the com bus, 
tion of the stearine of a downward turned lighted candle- 
the combustion of sulphur, carbon, and steel in oxygen. 
Hence: combustion is the combination 
with o xy g en. 

At the same time the student will notice that oxygen 
is a colorless gas, destitute of odor. 
It is a little heavier than atmospheric air, one cubic centi- 
meter weighing 1.430 milligrams. (Compare EL Phys., 
33). The presence of oxygen is always proved by the 
glowing shaving or splinter as above described 
(test for oxygen.) 

Larger quantities of oxygen are obtained by the disso- 
ciation of potassium chlorate. (Description of its crystals, 
El. Phys., 179.) It leaves potassium chloride, which is 



# In order that the experiment may succeed, the tube must not be moved, other 
wise the gas mixes with the air around the tube. 

fOne gram of mercuric oxide yields about 55 cc. of oxygen. 



52 Chapter III 



isomorphous with sodium chloride (El. Phys., 188). One 
gram of the potassium chlorate yields 280 cubic centime- 
ters of oxygen gas. To avoid the almost explosive rapid- 
ity of the evolution of the gas from this chlorate, the latter 
is mixed with manganese dioxide* (black oxide of manga- 
nese). Other methods of preparing oxygen have only im- 
portance to the teacher. 

101. The following experiment most beautifully dem- 
onstrates both analysis ( by dissociation ) and synthesis 
(uniting together). The student should foil nv the direc- 
tions to the letter. 

A minute quantity (1 cgr.) of mercuric oxide is heated 
in the closed end of a small blow-pipe glass tube (28), the 
closed end being heated in a small flame. The chemical 
process taking place is, as explained above, 98. 

Mercuric oxide -f- heat = Mercury + Oxygen. 

If now a few minute crystals of iodine (-J cgr.) are 
dropped into the tube, they will volatilize if the bottom of 
the tube is still hot — otherwise, heat gently. As the pur- 
ple vapors reach the mercury globules, the latter will dis- 
appear, and be replaced by a yellow (or red) ring. By 
gently heating the tube from the bottom till a little above 
the mercury mirror, and then permitting the whole to cool, 
beautiful microscopic crystals of ye 11 o w or bright 
red mercuric iodide will be seen in the tube 
under the magnifyer or by the microscope. If yellow 
crystals remain, they will slowly change to red ; by rub- 
bing them with a hard body (such as a glass rod or an iron 
wire) they will change quickly in color. If there was 
more of iodine than the mercury can combine with, a black 
ring of (partially crystallized) iodine will be seen above 
the red iodine; if not enough iodine had been taken, some 
metallic mercury will remain in the tube. 

♦This should itself be tested by heating a small portion of it with chlorate in an 
open cup; it organic matter be present, a alight explosion will take place and the 
oxide cannot be used for the preparation of oxygen. 



Dissociation and Electrolysis. 53 

Iodine has so far proved to be an element ; so has mer- 
cury. Hence we have in the above experiment the direct 
synthesis of two elements, iodine and mercury. The 
compound resulting is called mercuric iodide, as already 
stated. 

102. At a very high temperature water has been disso- 
ciated into two gases, namely: oxygen and hydrogen. 

By means of the galvanic current, water is much more 
easily decomposed than by means of heat. Compare El. 
Phys. 388, 390. The elctrolysis of water maybe 
exhibited to the class by Hofman's apparatus, figure 13. 
The two branches, A B, are about 30 cm. long ; they are 
completely filled with water, acidified with sulphuric acid, 
from the reservoir, C, by opening the stop cocks in A and 
B. Near the lower end of A and B platinum wires with 
foil have been fused through the glass, and serve as elec- 
trodes. 

When the poles of a battery of two or more Bunsen 
cups are connected with the platinum wires of A and B, 
a multitude of gas bubbles arise, and collect at the top of 
these tubes as shown in the figure. The gas in the tube 
which is connected with the positive pole of the battery is 
found to be oxygen; for the glowing shaving, held in 
the current of the gas produced by opening the correspon- 
ding stop-cock, bursts into flame. The gas in the other 
tube, connected with the negative pole of the battery, is 
called hydrogen; by opening the corresponding 
tube and bringing a flame near the gas current, the latter 
will be kindled, burning with a pale bluish flame. A dry 
glass vessel inverted over this hydrogen flame will become 
dim from the deposition of dew, indicating that the 
product of combustion of hydrogen is 
w a t e r.* 



*In order that this experiment may be quite demonstrative, the hydrogen gas 
should be carefully dri e d (157); but for common lecture purposes it may suffice 
to stale, shat the carefully dried hydrogen gives the same result as above. 



54 Chapter III 



It will also be seen that the volume of hydrogen gas is 
always exactly double that of oxygen. Hence, 

Water + galv. Electricy gives 1 vol. Oxygen -f 2 vols. 
Hydrogen. 

By careful experiments it has also been proved that a 
mixture of any volume of oxygen with twice as great a 
volume of hydrogen explodes by an electric spark or by a 
flame, and yields no matter but water* — while producing 
at the same time much heat. (Compare 47.) Hence, 

1 vol. Oxygen + 2 vols. Hydrogen -= Water + Heat. 

For the student's experiments on the gases produced by 
the electrolysis of water, the apparatus, figure 13, is most 
convenient. It consists of a bent glass tube, ABC, 1 cm. 
wide and each branch about 20 cm. long. One end, C, is 
closed by means of a cork and sealing wax; a platinum 
wire, to which a piece of platinum foil is attached, passes 
through the cork. In the open branch a like wire with 
foil is inserted. The tubo, is filled with acidified water 
from C to a little above the foil in A ; this is readily done 
by holding the tube with C downwards. The galvanic 
current is now passed through the water by touching the 
platinum wires with the connecting wires of the bactery ; 
always touch the wire in C with that pole which gives the 
gas you wish to examine. If yon therefore wish to ex- 
amine hydrogen, touch C with the negative pole ; if you 
want to experiment with oxygen, touch C with the posi- 
tive pole wire. 

When, by the collection of gas in C, the level in A B 
has been pushed quite up to the end, A, of the tube, dis- 
connect the battery, take out the wire from A B, close A 
with the thumb, invert the tube so that the gas is trans- 
ferred from B C to B A ; upon now removing the thumb 
the gas may be tested at pleasure. ■ 

*A dry glass held inverted over any flame of common combustibles (wood, stear- 
ine, kerosene, gas. etc.,) will be coated with dew or water. Hence these combus- 
itbles do contain hydrogen. 



Dissociation and Electrolysis. 55 



If your battery is not strong enough to fill the tube as 
stated, you may fill up A B by water, and proceed as 
above. 

103. If a considerable volume of hydrogen is collected 
the following properties of hydrogen may be recognized : 

Hydrogen is a colorless gas, without odor, and lighter 
than any other body, one cubic centimeter weighing only 
0.0896 milligrams, (El. Phys., 32). It has never yet been 
liquefied ; nor has it in any way been decomposed, so that 
it is considered a chemical element (see 96). It is easiest 
recognized by its combustibility. 

The latter fact requires great care in the experimenta- 
tion with hydrogen ; for if mixed with oxygen or common 
air, it will explode when the flame is brought in contact 
with the mixture. Hence the vessels wherein hydrogen 
is produced, should always be freed from air ; this is 
easiest done by continuing the evolution of hydrogen long 
enough.* 

104. If a considerable quantity of hydrogen is requir- 
ed it is usually obtained by the action of dilute sulphuric 
acid on zinc (172). One gram of zinc requires 1^ gr. of 
sulphuric acid, and yields about 3 centigrams of hydro- 
gen, which occupy a volume of about 330 cubic centime- 
ters. 

By means of the hydrogen thus produced various ex- 
periments may be exhibited by the teacher, especially the 
combustion of hydrogen and oxygen in the O x y h y- 
drogen bio w-p i p e. The flame of this blowpipe is 
exceedingly hot, but not luminous ; iron, and especially 
steel, burn in it with intense scintillations, and platinum 
fuses readily in the same. 

105. In electrolysis hydrogen passes to the negative 
pole ; hence hydrogen is considered the e 1 e c t r o-p o s i- 



*From time to time collect a test tube full of the gas, and carefully light it. If it 
burns without an explosion, the gas is pure, and free from air. 



56 Chapter III. 



ti v e component of water. For the same reason oxy- 
gen is considered the e 1 e t r o-n eg ati v e component 
of water. * 

In blue vitriol the metal copper is accordingly the elec- 
tro-positive component. 

By passing the galvanic current through all sorts of sub- 
stances, the metallic component invariably appears at the 
negative pole, either pure (as in the case of copper, sil- 
ver, mercur}' and other metals) or combined (as in the case 
of the more combustible metals, magnesium, etc). Hence, 
in general, the metals are the electro- 
positive constituents of compounds. 

Those elements or compounds which in electrolysis ap- 
pear at the positive pole, are termed electro-nega- 
tive elements, or compounds. 

♦For like electricities repel ; unlike attract each other. See El. Phys., 352. 



CHAPTER IV 



ELEMENTS AND COMPOUNDS. 



108. More than sixty substances have, so far, never 
been decomposed, either by heat (dissociated) or by the 
galvanic current (electrolysis) or in any other manner. 
These substances are therefore considered as chemic- 
al elements. 

All other substances are either compounds or mix- 
tures. (See 96 and 97.) 

107. The greater number of the chemical elements 
are metals, that is, bodies endowed with metallic 
lustre, and malleability. (El. Phys., MZ 208,.) The 
properties of opacity and tenacity are, In, different de- 
grees, associated with the above, as well^ as the eonducti- 
bility for electricity (El. Phys., 366) and heat (34), 

The elements not endowed with, these properties are 
termed metallo ids. 

The ancients knew only 9 of the substances now recog- 
nized as elements; namely the metals : gold, silver, mer- 
cury, copper, iron, tin, lead an^thetwo metalloids: sulphur 
and carbon. 

108. Since so many elements now are known,, it is im- 
portant to classify them carefully into groups- 
of elements closely resembling each other. A group of 
similar elements is called genus of elements. The 
individual elements, in each, geiMis are termed the s-p e- 
c i e s of elements. 

In this volume we consider only MB genera, together- 
with two genera each, represented by aaiy oB t e species .. 
8- 



58 Chapter IV, 



We shall name these genera by attaching the suffix -oids 
to the characteristic part of the name of the most promi- 
nent element of the gen us. * 

The following is a list of the genera of elements in the 
proper order : 





GENUS. 




SPECIES. 


LATIN NAME. 


1. 


Kaloids, resemblir 


g Potassium 


(Kalinin). 


2. 


C a 1 c o id s 


kt 


Calcium. 




3. 


C a d m o i d s, 


a 


Cadmium. 




4. 


C u p r o i d s, 


u 


Copper. 


(Cuprum.) 


5. 


F e rr o i d s, 


u 


Iron 


(Ferrum) 


6. 


T i t a n o id s, 


u 


Titanium. 




7. 


P h o s p h o i d s, 


u 


Phosphorus. 




8. 


Sulphoids, 


u 


Sulphur. 




9. 


Chloroids, 


a 


Chlorine. 





Between 3 and 4: stands mercury (Hydrargyrum), the 
only representative of the Hydrargoids. The 
element hydrogen may be placed both at the top and at 
the bottom of this list ; in the first place if it is metallic in 
its relations, (and may be called hydrogeniu m), while 
in the latter case it acts like a metalloid. Also Boron and 
Tin are here given as single elements — representatives of 
genera not here described. 

109- The order of the genera above given is de- 
termined by the deportment of the ele- 
ments in high te m prat u res. The least 
fusible and volatile is placed in the middle. The most 
fusible and volatile are at the top (genus 1) and at the 
bottom (genus 9); the metals standing above, the 
metalloids below. The upper elements in this table 
are decidedly elect ropositive;f the lower equally 



*Only if that element has a name unfit to take the suffix shall we name the genus 
after one of its less important members ; as in case of genus 3 and 6. 

tDetermined especially by the deportment of compounds in electrolysis. The 
element passing to the negative pole is electro-positive, see 105. 



Elements and Compounds. 59 

e 1 e c t r on egative; the middle are positive in refer- 
ence to the lower, and negative in reference to the upper. 
The different species in each genus are arranged from left 
to right in the order of their specific gravity. 
Thus the cuproids are copper, silver and gold ; they are 
given in this order, because copper has the lowest, gold 
the highest, specific gravity of the three. 

110. But the tabular view of the elements cannot readi- 
ly be represented if the full name of the element is to be 
entered in the same. Besides, it is of very great practical 
importance to adopt some abbreviations or symbols 
for the elements in order to make all references to them 
as simple as possible. 

The symbols of the elements were de- 
vised by Berzelius, and consist in the 
characteristic letters of the Latin- 
ized name of the elements. Thus potassi- 
um has the symbol K a, the characteristic letters of the 
Latinized ( Arabic ) name Kalium. Zinc has the 
symbol Z n (Latinized, zincum), lead P b (plumbum, Lat- 
in), iron F e (ferrum), gold A u (aurum). 

In the same manner we use as symbol of the 
genus the characteristic Greek let- 
ters of the name of g e n u s. 

112. In this way results the following natural 
clssification of the elements, first published by the 
author in 1867 : 



60 




Chapter IV. 






GENERA. 






SPECIES. 




r 


H... 




. . . electro pos 


sitive. 




1 Ko. 


Li 


Ma 


Xa 






2 Xa 






Ca 


Sr 


Ba 


3 Kd 




Mg 


Zn 


Cd 


Pb 


r r 








•• 


Hg 


4 Ko 






Cu 


Ag 


Au 


5 2V 




Al 


18 


Rh 


Ir 


6 TV 


c 


Si 


Ti 


Pd 


Pt 




Bo 






Sn 




7 


N 


P 


As 


Sb 


B 


S (9 


o 


S 


Se 


Te 




9 X 


Fl 


CI 


Br 


Io 




r 


H... 




electro-r 


legative. 





The symbol 2d stand for the following varieties of el- 
ements : 

16 Cr Mn F e M Co Ur 

112. In order to learn the signification of these sym- 
bols, we give an alphabetical list of the same, together 
with the common name represented by the symbol. The 
Latin name has been added in all cases where the deriva- 
tion required it. 



Elements and Compounds. 61 



SYMBOL. NAME, COMMON. LATIN. 

Ag Silver A rgentum. 

Al Aluminium. 

As Arsenic. 

Au Gold Aurum. 

Ba Barium 

Bi Bismuth 

Bo Boron 

Br Bromium 

C Carbon 

Ca Calcium 

Cd Cadmium 

CI Chlorine 

Co Cobalt 

Cr Chromium 

Cu Copper Cuprum. 

Fe Iron Ferrum. 

Fl Fluorine. 

H ...... .Hydrogen. 

Hg Mercury Hydrargyrum. 

lo Iodine. 

Ir Iridium. 

Ka Potassium Kalium. 

Li .Lithium. 

Mg Magnesium. 

Mn Manganese. 

N .Nitrogen. 

Na. ...... Sodium Natrium. 

Ni Nickel. 

O .Oxygen. 

P . . . . Phosphorus. 

Pb Lead Plumbum. 

Pd Palladium. 

Pt Platinum. 

Kh Rhodium. 

S Sulphur. 



62 Chapter IV. 



SYMBOL. NAME, COMMON. LATIN. 

Sb Antimony Stibium. 

Se Selenium. 

Si Silicon, 

Sn Tin Stannum. 

Sr Strontium. 

Te Tellurium. 

Ti Titanium. 

Ur Uranium. 

Zn Zinc. 

113- The symbols of the genera, also in alphabetic 
order, are : 

SYMBOL. NAME. PRONUNCIATION OF SYMBOL. 

6 Sulphoids Theta. 

Ka Kaloids Kappa-alpha. 

Kd Cadmoids Kappa-delta. 

Ko Cuproids Kappa-upsilon. 

It Ferroids Sigma-iota. 

Id Sideroids* Sigma-delta. 

Tt Titanoids Tau-tau. 

Y Pantoids Upsilon. 

Ty Hydrargoids .... .Upsilon-gamma 

Phosphoids p . . Phi. 

X Chloroids .....Chi. 

Xa Calcoids Chi-alpha. 

114. The studentf should make himself quite familiar 
with the following simple characteristic of 
the system of the elements : 



♦The group Cr., Mn., Fe., INI., Co., all very nearly alike, as if they were varieties of 
the species Fe. The element Ur., also is allied to this group. 

fThe teacher should exhibit as many of the elements as possible, in small speci- 
men tubes. Also some of the phenomena— as combustion of Ka. on water- 
should be shown to the class. On a wooden tablet, one meter square, the systematic 
classification, 112, should have been painted, so that the teacher with chalk can 
write boundary lines, etc. The student should enter these lines on the blanks of 
112, printed in the Journal. See fig. 15. 



. Elements and Compounds. 63 

I. The elements above the full drawn boundary line, 
(figure 15) have metallic luster; the elements below the 
line have no metallic luster. The former are usually 
called metals, the latter metalloids. 

II. The metals below and to the right of the dotted 
line are called heavy metals, because their spe- 
cific gravity is above 5 ; the other metals are called light 
metals. 

III. The kaloids are most strongly electro-positive ; 
the chloroids are most strongly electro-negative. The 
other genera have been arranged according to their elec- 
tric property ; each genus being positive in reference to 
the genera below, and negative to the genera above.* 
Accordingly Aluminium and all of the heavy metals are 
found both as electro-positive (towards the metalloids) 
and as electro-negative (towards the kaloids and calcoids) 
in combinations. Compare 109. 

IY. The elements below the fine drawn line (figure 
15) are gaseous ; all the other elements are solids, except 
Bromine and Mercury, which solidify respectively at — 7° 
and — 40°. Of the gases, chlorine has been liquefied ; 
but hydrogen, oxygen, and nitrogen have not yet been 
liquefied, and are therefore called permanent gases. 
Fluorine is but very little known. 

115. The following simple characteristic of 
the genera should be studied in the same manner as in 
114: 

1. Kaloids, Ka. Yery soft, lighter than water, 
very fusible, exceedingly volatile and combustible, 
white metals, coloring* the flame ; cannot be reduced 



*Hydrogen at the top is the metallic hydrogenium of Graham; it is elec- 
tro-positive, hut as yet only known alloyed with Palladium. 

Hydrogen at the hottom is electro-negative, occurring in Hydrates. See further 
on. 



64 Chapter IV. 



by the blow-pipe. (See 25 and 95.) Do not impart color 
to their compounds.* 

2. C a 1 c o i (I s, Xa. Rather hard ; heavier than water ; 
fusible, not volatile; highly combustible; whitish (yellow) 
metals, coloring the flame. In regard to compounds and 
reduction as 1. 

3. Cad m o i d s, Ko. Rather Soft ; moderately heavy; 
very fusible and volatile ; bluish white metals; com- 
bustible, coloring the flame but faintly. Impart no color 
to their compounds. All reducible by blow-pipe except 
the most combustible, Mg.f 

Mercury, Hg. Liquid ; very heavy ; very volatile ; 
not readily combustible; grayish white metal. Rather in- 
termediate in its properties between Ag and Pb. 

4. C u p r o i d s, Kv. Moderately hard, heavy, fusible; 
faintly volatile metals, possessing metallic luster and mal- 
leability in the highest degree. iS^ot combustible except 
Cu, which colors the flame green. Very easily reducible 
by blow-pipe ; all compounds of Ag and An dissociated 
by heat. Compounds of copper usually colored (common- 
ly green and blue). 

5. Ferroids, 2V. Hard, heavy, difficultly fusible, 
non-volatile, grayish white metals, some of which have 
highest degree of tenacity (Fe). The lighter ones com- 
bustible ; all but the light metal, Al, reducible before the 
blow T -pipe. 

The s i d e r o i d s, Id, embrace five metals most closely 
allied to iron ; they occur usually together, and strongly 
color their compounds, They are magnetic, 
especially Fe, !S T i, Co. The element Ur is related in the 
sideroids. 



♦Teacher : burn Ka on water; obs. flame. Show metal properly incased between 
1 wo test tubes (sliding into one another) and bees' wax. Na is now manufactured in 
large quantities. 

|Burning Mg. wire before class. Student practice on minute portions of Mg., Zn. 
and Pb. [I cgr. each] in o-fl of plow-pipe. Note color and size of incrustation. Com- 
pare — . 



. Elements and Compounds. 65 

6. T i t a n o i d s, TV. Mostly heavy, all infusible, 
non-volatile elements ; the lighter ones* combustible and 
non-reducible ; the heaviest non-combustible and asily re- 
ducible. 

7, 8, 9. The elements of these genera resemble the 
type-element (P, S, CI,); otherwise the properties gradu- 
ally increase towards the metallic with the in- 
crease in specific gravity, that is, towards the right in 
each genus. Thus Bi has high metallic luster, is usually 
called a metal, but it is brittle. 

In regard to combustibility and reductibility, we must 
refer to the subsequent parts of these elements. 

116. The student may now ascertain the pyrognos- 
tic properties of the principal elements, that is, 
the deportment of the element in high temperature. 
Thereby the above characteristic, 115, will become more 
tirmly grounded in his mind. 

The teacher should give the student a few minute frag- 
ments (each about one centigram) of the element ; also 
blow-pipe and charcoal, see 25.) The student carefully 
notices the physical properties (see El. Phys., 216) es- 
pecially the four optical and the molar properties ; then 
heats one of the fragments steadily in the fusing point of 
the blow-pipe flame, and carefully observes : fusing, vola- 
tilization, combustion (flame coloration), and incrustation, 
as to color and size, both hot and cold. Also notices odor 
and fumes, if any. Finally compares results to the gen- 
eral characteristic in 115. 

If an additional larger piece is given, the student may 
also determine hardness, H, and specific gravity, G; other- 
wise, the teacher better state these two properties on the 
label, for the student to enter in his description in paren- 
thesis. 



*The common varieties of coal arc impure carbon. 



66 Chapter IV. 



The properties should be recorded in the following 
order : 

No. . . .Description of 

Optical: Opacity — Luster — Color — Streak. 

Molar : H G Cleavage: malleable ? brit- 
tle ? 

Pyrognostic: Fus. — vol. — combust? incrust., etc., etc 
Odor ? Fumes % Magnetic ? 

117. After the student has thus become personally ac- 
quainted with pyrognostic properties of some of the most 
common elements, he may examine, some of the com- 
pounds of the elements in the reducing flame. First, the 
substance alone ; next, the substance mixed* with about 
twice its amount of sodium carbonate. He may then 
often be able to determine the metal in the compound. 

Kesults should be recorded in the Journal precisely as 
in 116. 

It is absolutely essential that the student should take no 
larger quantity than directed — of elements never more 
than about a centigram, and of compound rather less yet. 
The blow-pipe flame should be steady, and well defined ; 
compare 23. 

II. CHEMICAL NOMENCLATURE. 

118. All matter being composed of the comparatively 
small number of chemical elements, it follows that the num- 
ber of chemical compounds is practically infinite. On this ac- 
count it is highly important that these compounds should 
be classified and named according to some simple and 
rational method. The following classification and nomen- 
clature is quite generally used ; for the sake of further 
simplification we have added a concise notation. 

119- Substances are first classified into Monaries, 
Binaries, Ternaries and Serials. 

*On a piece of paper, by blade of penknife. 



Chemical Nomenclature. 67 



Monaries are the chemical elements themselves. Bi- 
naries are compounds of any two elements. Ternar- 
ies are combinations of any three elements. The serials 
are peculiar compounds of carbon, with one or more of 
the following elements : hydrogen, oxygen, and nitrogen. 
They occur quite abundant in animals and plants, and 
therefore are often termed organic compounds. But 
many of these serials have been prepared from their ele- 
ments in the laboratory, mostly by successive condensa- 
tions or additions, so that their particles appear to form 
strings or series of particles of the constituent elements. 
Hence the name whereby these compounds here are des- 
ignated.* 

Compounds containing water in addition are commonly 
classified as hydrated in connection with the com- 
pound resulting by the removal of the water. Thus blue 
vitriol is classified with the sulphates. (See 92.) 

120- The elements are named as explained above. 
Any element is often symbolized by the letter R (ab- 
brev. of r a d i c a 1). Any electro-positive element will be 
designated by the Greek letter tt ; any electro-negative 
element by the Greek letter v. Any element interme- 

*The following may serve to give a more distinct idea of what is meant by serial 
compounds: 

When petroleum is subjected to careful fractional distillation, a number of vol- 
atile liquids are obtained differing from one another by about the same number of 
degrees in boiling point; the specific gravity of these liquids increases quite regularly 
with the boiling point, and the specific gravity of the vapors increases from one to 
the next by exactly seven times the amount of the specific gravity of hydrogen, 
that is by 0.627 mgr. for the cubic centimeter. These substances furthermore all 
consist of carbon and hydrogen in very nearly the same proportion. These are 
called Paraffin s, and distinguished as the I., II., etc., in the series of Paraffins. 

The nth member in this series contains 1 plus — part of hydrogen for each 1 of car- 

n 

bon ; the specific gravity of its vapor is exactly 1 plus 7. n times the specific gravity 
of hydrogen ; the specific gravity in the liquid form is about 0.08 plus 0.43. n. The 
members [n = 1, 2, 3 and 4] are gaseous at common temperatures, while the next 
following are liquids, and the highest members are solids. 

Thus these compounds form a regular series in every respect ; and it is in this 
sense that they may be called serial compounds. Of such series of compounds a 
great many are known, and the organic materials have all a composition of pre- 
cisely this serial nature. 



68 Chapter IV. 



diate, combining with either of the above, may be desig- 
nated by e. 

121. A Binary is a chemical combi- 
nation of any two elements. Since now 
any element is either electro-positive or electro-negative 
in reference to any other, a binary must always consist of 
one element which is electro-positive in reference to the 
other. Hence any binary may be represented by 

the electro-positive always being written first. Most com- 
monly >r is a metal and v a metalloid. (Compare 114, 
also 101.) 

The scientific name of such binary consists of two 
words, namely, the full name of the electro-positive 
element, ;r, followed by the essential portion of the name 
of the electro-negative element, v, to which the suffix ide 
has been appended. Hence the name of any binary may 
be represented by 

7T y-ide. 

For example, the binary resulting from tt = Mercury 
and v = iodine in 101, is called Mercury iodide. Oxygen 
combined with mercury gives Mercury oxide. 

For the sake of brevity these names may also be written 
by using the symbols, thus : Hg Io-ide Hg O-ide. 
- 122. However, at times the same two elements com- 
bine in more than one proportion. Thus mercury and 
iodine combine in two different proportions, namely, one 
gram of mercury with 1.27 gr. iodine in the above men- 
tioned iodide (see 101), but also with half as much iodine 
(0.63 gr.) in a greenish iodide. These are distinguished 
by appending the suffix -i c or -o us to the characteristic 
part of the electro -positive. 

The compound Tr-i c v-i d e contains more of the elec- 
tro-negative, the compound --o u s v-i d e contains less 
of the electro-negative. 



Chemical Nomenclature. 69 



Accordingly the red iodide of mercury is called in e r- 
curie iodide, the green is called mere u r o u s 
iodide. The mercuric oxide used in 99 and 101 is red ; 
contains more of oxygen than the black oxide of mercury 
which is properly called mercurous oxide. 

Abbreviated by the use of the &3 r mbols of the elements, 
these names will be Hg-ie Jo-ide ; Hg-ous Io-ide ; Hg- 
ic O-ide, Hg-ous O-ide. 

123- The proper classification of the binaries is by the 
negative element. Thus we describe not the various 
biaries containing the same tt, but those containing 
the same v in the same section. Hence we describe 
as separate classes of binaries the oxides (v — O), chlo- 
rides (p — CI), iodides (p = Io), sulphides (p = S ). In 
each of these the particular species is determined by the 
electro-positive n. 

124. A ternary compound is a chemical 
combination of any three elements. The 
most electro-positive of these will be denoted by 7r, the 
most electro-negative by p, the intermediate by s. Hence 

7T S P 

represents any ternary. 

125. By far the most common case is £ = O, that is, 
oxygen is the intermediate element in most ternaries. 
These oxygen ternaries are called 

n p-sl t e 
or 7i p-i t e 

according as the amount of oxygen is greater or less. 
Thus copper sulphate and copper sulphite are both terna- 
ries of copper, oxygen and sulphur; but the first contains 
more of oxygen than the latter — Abbreviated Cu S-ate 
and Cu S-ite. 

Also here the suffixes -i c and -o u s are appended to 
7i as explained in 122. Cuprous sulphate contains rela- 



70 Chapter IV. 



tively less of sulphur than cupric sulphate — Abbrevia- 
ted Cu-ous S-ate and Cu-ic S-ate.* 

126. If the intermediate element £ in the ternary is 
not oxygen, it is either sulphur, chlorine, bromine, 
iodine, fluorine or the so-called compound radical cyano- 
gen. In these cases the characteristic portion of the name 
of the intermediate element e is used as a prefix to the 
name v. Hence the name of these ternaries has the gen- 
eral form 

k e-v-ate 

or it s-v-ite 

where again both ar-i c and n-o u s are nsed.f 

Thus potassium cyano ferrate is a ternary, composed of 
potassium as the most electro-positive, iron as the most 
electro-negative, and cyanogen as the intermediate element. 
What is potassium chloro-platinate ? Sodium fluo-alumin- 
ate ? These names may be written in the following ab- 
breviations : Ka Cl-Pt-ate; Xa Fl-Al-ate ; Ka Cy-Fe 
-ate. 

127. The nomenclature of the serials cannot here be 
treated of; it must suffice to mention a few of the most 
prominent classes of serials. 

The Hydro-carbons are serial binaries of carbon 
and hydrogen. In Petroleum, our illuminating fluids, in 
illuminating gas, we have mixtures of these. Some vola- 

*If there are still further proportions of oxygen, then the prefix peris added for 
more, and hypo- for 1 e s s of oxygen. 

From the least to the greatest amount of oxygen thus six different grades, 
namely : hypo-v-ite, v-ite, per-v-ite, hypo-vate, v-ate. per-v-ate. 

This number is quite sufficient. For \> = CI, N, P, several of these names are re- 
quired. 

fTernaries can frequently be prepared by direct synthesis of two binaries. The 
binaries JT £— ide and V £— ide, will, if united, give the binary Jt £— Vate. Hence, 
many chemists call such ternaries double binaries. For example, potassium 
Chloride and platinum chloride combine directly; they yield the ternary potassium 
chloroplatinate. Many chemists call this compound, however, a double chloride of 
potassium and platinum. 

Although in Pt Cl-ide, the chlorine is the negative element, in Ka Cl-Pt-ate it is 
the intermediate, between the two metals, the electro-positive Ka and the 
electro-negiatve Pt. 



Chemical Nomenclature, 71 



tile oils also belong to this class. See note to 119. 

The c a r b o-h y d r a t e s are serial ternaries of carbon, 
oxygen, and hydrogen, the latter two in the proportion in 
which they would form water. Sugar, gum, starch, wcody 
fibre are such serials. 

Hydro-carbons with a certain amount of oxygen are 
ethers; with more oxygen they form alcohols, 
with most oxygen acids result. Common ether, alco- 
hol, and acetic acid form good examples. 

Certain compounds of nitrogen with carbon, hydrogen, 
and oxygen are called alcaloids. Such are strych- 
nine, morphine, quinine. 

128. The preceding notions of chemical nomenclature 
will enable the student to tell the elements in a substance 
if the correct scientific name is given to him. Again, if 
by synthesis compounds are built up, the student will 
be able to give the proper name to each. 

We shall now proceed to the synthesis of the principal 
binaries and ternaries. 



CHAPTER V. 



ACIDS AND BASES. 



129. Phosphorus is ignited at a low temperature* 
and burns with emission of a brilliant light, producing at 
the same time a white smoke. The white particles are 
therefore phosphoric oxide; if the supply of air 
is limited, phosphorous oxide results. 

Both of these oxides are readily absorbed by water, 
which thereby assumes an acid taste and turns blue lit- 
mus paperf red. Hence the solution of these oxides in 
water are termed acids; respectively ph osphoric 
acid and phosphorous acid. 

For lecture purposes the teacher should burn about -J- 
gram phosphorus, supported on an iron d eflag rating 
spoon in a large, loosely closed, dry flask ( figure 16) ; 
then add some water, which will dissolve the dense white 
fumes and yield a dilute solution of phosphoric acid. If 
this solution is evaporated, a syrupy liquid of concentrated 
phosphoric acid results, finally pure solid phosphoric 

*Hence phosphorus is to he preserved under water, and handled with much care. 
Only a small piece is used at a time. If to be cutoff, this is done under water. 
Before use for combustion phosphorus is carefully dried between blotting paper. 
The dried phosphorus only should be used for combustion ; to light it, touch it. 
with a heated wire. 

fThe so-called litmus is a vegetable blue coloring material. It dissolves 
partly in water. Fine printing paper soaked in such solution and dried constitutes 
the blue litmus paper. It is cut into small strips, about 2 mm. wide and 30 mm 
long, called blue test paper. These strips are preserved in the dark [closed 
boxes, etc.,] for by light they are soon bleached. 

When the blue litmus solution is just reddened by the least possible 
amount of a dilute acid [sulphuric] and paper drawn through the reddened solution, 
we obtain the so-called red litmus paper, which is cut and preserved pre- 
cisely as the blue paper. For its uses, see below. 



Acids and Bases. 73 



acid will be obtained (the so-called glacial phosphoric 
acid). When a small portion of this acid is thrown into 
water, it dissolves, heating the water very much. 

Since phosphorus in combustion necessarily ( 100 ) gives 
an oxide, and since water is also an oxide ( hydrogen oxide, 
see 102), it follows that phosphoric acid is a 
ternary, composed of hydrogen, oxygen, and phos- 
phorus. The latter is electro-negative in regard to the 
first.. Oxygen is the intermediate element, so that the 
scientific name of this ternary is hydrogen phos- 
phate. Abbreviated Ii P-ate. Compare 125. 

If the tube (130) with both its branches is held nearly hor- 
izontal, the phosphorus cannot get as much oxygen, and 
phosphorous oxide will result. This will yield hydrogen 
phosphite when dissolved in water. Abbreviated H 
P-ite. 

A still more imperfect combustion of phosphorus yields 
the so-called hypophosphorous oxide, which in water pro- 
duces hydrogen hypophosphite. 

All of these solutions are acid ( i. e, redden blue test 
paper) ; hence they are often spoken of as the acids of 
phosphorus. 

130. The following apparatus is much more suitable 
for all the experiments on combustion and the products 
of combustion described in this section. 

The apparatus consists of a combustion tube, 
A, figure 17 ; one or more absorption tubes, B, 
and our aspirator, described El. Phys., 136, 137. 

The combustion tube is of glass, from 3 to 6 mm. in- 
ternal diameter, and at least 1 decimeter long. It may 
be gently bent, as the figure shows. The combustible is 
placed in the middle of this tube, and ignited by a hot 
wire (P) or by heating the tube from without (C, S). 

The absorption tube consists of a common test tube 
closed by a stopper through which pass two glass tubes as 
shown in the figure. The glass tube connected with the 
10 



74 Cliapt 



er 



combustion tube by a rubber tube passes to near the bot- 
tom of the test tube ; the other glass tube, connected with 
the aspirator or with the next absorption tube, passes but 
just through the stopper. 

By successively placing thin square boards under the 
first flask of the aspirator, a flow of air is kept up through 
the apparatus precisely as rapid or slow as may be re- 
quired. The state of combustion in the tube, A, indicates 
whether the current of air should be accelerated or re- 
tarded. 

In these experiments it is best to use two aspirator tubes, 
the first being dry, the second containing some water. In 
this way the combustion of as much as one decigram may 
be safely performed by the student, and enough of the 
product of combustion will be shown f r e e in the firs 
absorption tube, and in combination with water in the 
second. 

131. The high combustibility of phosphorus permits 
us to make use of phosphorus for the analysis of atmos- 
pheric air. About -J- gram of dry phosphorus is placed 
on an iron dish (sand bath without sand) supported on a 
tripod under a bell glass, standing in a large vessel with 
water. The phosphorus is ignited with a hot wire, intro- 
duced through the tubulature of the bell glass ; as soon as 
ignited, the wire is withdrawn, the tubulature closed by a 
glass stopper. The combustion will cease when there is 
no more oxygen in the bell glass; the unburnt phosphorus 
will remain. The bell glass will be filled with white va- 
pors of phosphoric oxide (mainly). In about an hour they 
will have dissolved in the water. 

The level of the water will be observed to have risen 
about one-fifth up the bell glass. Furthermore, a burning 
taper introduced through the tubulature, will immediately 
be extinguished in the residual gas. This gas, thus unfit to 
support combustion, is called nitrogen. 



Acids and Bases. 75 



If a volume of oxygen, equal to the one-fifth volume 
lost, be added again to the nitrogen, a mixture will result 
perfectly identical with the air originally used. 

Accordingly it is demonstrated, that atmospheric 
air is a mixture of 4 / 6 nitrogen and 
Vs oxygen. 

132. All combustions going on in the air are due to 
the oxygen in the same. But in order to bring the neces- 
sary volume of oxygen to the fire by the draft of 
our fireplaces, we must supply at least five times as 
great a volume of air. The heating of the remainingjii- 
trogen — even if all the oxygen be consumed — constitutes 
one of the wastes of fuel which it is impossible to remedy. 
Even if pure oxygen could be obtained for our furnaces, 
we would not be able to use it, because the iron fireplace 
would then burn even more brilliantly than the fuel in 
the same. See 100. 

We shall in the third volume (C osmos) demonstrate 
that animal life is chemically a process of combustion. 
If in breathing we inhaled pure oxygen instead of 
the common air (oxygen diluted in four times its volume 
of nitrogen) we would very rapidly die of fever. Pure 
oxygen thus is a poison ; but atmospheric air, containing 
20 per cent of oxygen, is absolutely essential to life. 

133. If a small piece of sulphur is burnt in a common 
flask, we shall notice a pale blue flame and the so-called 
odor of sulphur. The latter is exclusively* due to the 
gaseous product of combustion of sulphur. This product 
is usually termed sulphur d i-o x i d e.f It is a color- 
less gas, distinguished by the odor of burning sulphur. 
One cc. of the gas weighs 2.861 mgr. By cooling this gas 
to 18 degrees, it liquefies. 



•For a solid, which like sulphur does not volatilize at common temperatures, 
cannot possess any odor. 

fBecause theory shows that 2 particles of oxygen have combined with each one 
particle of sulphur. 



76 Chapter V. 



134. It" now a little water is added to the flask, the 
gas will soon dissolve, especially upon some agitation. 
The solution resulting is also an acid, because it reddens 
blue litmus paper ; (see 129). It is called sulphur- 
ous acid. It bleaches vegetable colors, and is ex- 
tensively used on that account. The litmus paper is first 
reddened, then bleached. 

Sulphurous acid is evidently also a ternary, composed 
of hydrogen, oxygen, and sulphur. Since S is the nega- 
tive, O the intermediate (combined with S in the sulphur 
di-oxide, and with H in the water), the scientific name of 
this acid must be hydrogen sul phi t e, or H S- 
ite. 

This solution will not bear evaporation. By evapora- 
tion it again is dissociated into its constituent binaries. 
Thus by mixing or solution : 

Hydrogen Oxide + Sulphur dioxide gives Hydrogen 
sulphite ; but again by heating, 

Hydrogen sulphite gives Hydrogen oxide + Sulphur 
dioxide. 

The ready dissociation of this acid should be constantly 
kept in mind. 

135- If, however, the sulphurous acid is left exposed 
to the air, it will soon stand evaporation without giving 
off sulphur dioxide ; but it will then no longer possess 
bleaching properties. Hence it is no longer sulphur- 
ous acid ; by proper experiments it has been demonstra- 
ted to have taken up more oxygen from the air. 
This fact can also be proved by the change taking place 
rapidly, if air is blown through the sulphurous acid. 
Hence the hydrogen sulphite has become hyd rogen 
sulphate, orH S-a t e. Evaporation of the dilute acid 
obtained above yields a strong acid identical with the well- 



Acids and Bases. 77 



known sulphuric acid of commerce.* Accord- 
ingly sulphuric acid is hydrogen sulphate. 

More easily the addition of oxygen is accomplished by 
holding a shaving, moistened with strong nitric acid, into 
the flask containing the sulphur dioxide and water, before 
shaking and mixing. See above, 133, 134. 

136. A piece of charcoal burnt in a dry flask (see 
129) or much better in the apparatus, 130, a colorless gas 
will result, destitute of odor. This oxide of carbon is called 
carbon dioxide.f It is heavier than atmospheric 
air, one cubic centimeter weighing 1.967 milligrams. It 
can be condensed to a 1 i q ui d by pressure at all tempe- 
ratures below 31°. By rapid volatilization of this liquid 
some of the dioxide solidifies to white snow-like crystals. 

Since this gas is colorless and odorless, we require some 
simple test to prove its presence. L i m e w a te r — 
the clear filtrate from slaked lime soaked in water — be- 
comes turbid when brought into this gas, as may be ex- 
hibited by using a rather wide tube as pipette, and holding 
this pipette with lime water into the above flask filled 
with carbon dioxide. The lime water will quickly become 
quite turbid or milky. 

This gas is, of course, produced in all our fireplaces 
where carbon or carbonaceous fuel is used. 

137. -By pouring some water into the flask filled with 
carbon dioxide (136) and shaking, the gas will be absorb- 
ed. Hence we have 

Water = H O-ide 
and Carbon dioxide and C, 



*This acid, often termed o i 1 of vitriol, is manufactured in immense quan- 
tities. By the burning of sulphur they obtain sulphur dioxide, which gas is con- 
ducted into immense lead chambers where steam (water = H O-ide) and oxygen 
convert into Hydrogen Sulphate. The dilute acid of the chambers is evaporated 
in lead pans, and concentrated in platinum stills. 

*In all older works on chemistry this oxide is termed carbonic acid: but 
this is a misnomer, the gas has no acid properties whatever. An acid results when 
the gas is combined with water. S«e 137. 



78 



Chapter V. 



giving a ternary compound of H, O, and C, and called 
Hydrogen Carbonate; abbreviated H C-ate. 
This ternary has also acid properties, and therefore is cor- 
rectly called Carbonic Acid. 

It is now manufactured on a large scale in a rather con- 
centrated form by saturating water with the carbon diox- 
ide gas under pressure at the freezing point (the vessel 
being placed in ice). This solution of carbonic acid is 
known as soda water. 

138. Besides the above acids, the synthesis of which 
has been given, a great many other acids are more or less 
generally used. In the subsequent their composition will 
established when their methods of preparation will be de- 
scribed. Here it may be sufficient to indicate their 
composition by the scientific name added to their common 
or vulgar name : — 



VULGAR NAME. 


SCIENTIFIC NAME. 


Nitric acid. 


Hydrogen Nitrate. 


Chloric 


u 


cc 


Chlorate. 


Boracic 


cc 


a 


Borate. 


Silicic* 


cc 


ct 


Silicate. 


Arsenious 


u 


u 


Arsenite. 


Arsenic 


a 


a 


Arsenate. 


Chromic 


a 


a 


Chromate. 


Manganic 


a 


u 


Manganate. 


Permanganic 




u 

u 


Permanganate. 


Hydrochloric 


Cloride. 


Hydrobromic 


a 


u 


Bromide. 


Hydriotic 


a 


u 


Iodide. 


Hydrofluoric 


it 


u 


Fluoride. 



♦Not to be confounded with Silicon oxide, commonly but incorrectly called sili- 
cic acid. Compare foot note to 136. 



Acids and Bases. 



79 



VULGAR NAME. 

Hydrocynanic acid. 



SCIENTIFIC NAME. 

Hydrogen Cyanide. 



Hydrofluosilicic " 
Hydroferrocyanic " 
Hydroferricyanic " 



Fluosilicate. 

Cyanoferrate. 

Cyaniferrate.* 



Acetic a " Acetate. 

Oxalic " " Oxalate. 

Tartaric " " Tartrate. 

139. If a small piece of potassium is burnt in the 
combustion spoonf of the flask 129 — all being perfectly 
dry — the purple flame will be seen quite beautifully, the 
flask will be partially filled with white fumes ( because 
the metal is so volatile) and a whitish (or yellowish) resi- 
due will remain in the spoon. This compound is evident- 
ly Potassium Oxide; abbrev. Ka O-ide. 

Potassium oxide is also exceedingly soluble in water; 
if the solution is evaporated to dryness, the oxide does 
not reappear, but a substance containing hyd r ogen 
as well as oxygen and potassium remains. 

Since now potassium is the most electro-positive of all 
elements, oxygen the intermediate, hydrogen ought here 
to be consider as electro-negative ; hence this new binary 
must be called Potassium Hydrate; abbrev. Ka 
H-ate. 

It is not an acid, for the blue litmus paper is not red- 
dened by it. But if a red litmus paper is dipped into the 
solution of this new body, we see the red paper turn 
blue again. Potassium Hydrate accordingly acts in a 
manner exactly the reverse of the acids. It is called a 



*Strictly the last two acids should be distinguished as hydrous and h y d r i c 
cyanoferrates ; but the above giren names more nearly conform to the vulgar 
ones in use. 

fBetter in the glass tube, 130. No absorption tube nor aspiralor is required. 



80 Chapter V. 



base. Its taste* is also quite different from what we 
call acid, or sour. Sodium yields in the same manner 
sodium oxide and the base sodium hydrate. 

140. The common aqua ammonia also turns red 
litmus paper blue ; it is also a base, and according to its 
composition it is termed ammonium hydrate. Am- 
monium has been found to be a compound of nitrogen and 
hydrogen, acting, under most circumstances, as if it were 
an element ; it is therefore termed a compound radical, 
and designated by the symbol Am. Ammonium hydrate 
thus may be abbreviated Am H-at e. 

But if aqua ammonia is heated, it dissociates into water 
and a colorless, very pungent gas, called ammonia, 
which passes off. This gas is absorbed with great avidity 
by water, reproducing the aqua ammonia. One cubic 
centimeter of gaseous ammonia weighs 0.763 milligrams. 
It has been condensed to a liquid by a pressure of about 
7 atmospheres at common temperatures. 

How ammonia and ammonium hydrate are obtained 
in immense quantities will be shown further on. 

141. If limestone, marble or calcite crystals, are heat- 
ed intesely in a glass tube communicating by a rubber 
tube with any apparatus for the collection of gases (El. 
Phys., 127), we shall see this receiver gradually fill with 
a colorless gas. Upon farther investigation this gas proves 
to be carbon dioxide ; (see 136). 

The white mass remaining in the tube will be recog- 
nized as burnt lime or quick lime; it has been found 
to be the same substance which results when the metal 
calcium is burned. Accordingly, the white residue is 
Calcium oxide. 

Hence limestone, marble, or calcite dissociate at 
a bright red heat into calcium oxide and car- 

♦All these bodies should be tasted in minute portions much diluted 
with water. In fact, the student better abstain from tasting any of the chem- 
icals, except especially requested to do so by a competent teacher. 



Acids and Bases. 81 



bon dioxide. Therefore, the above common sub- 
stances — limestone, marble, calcite, are calcium ca> 
b o n at e according to chemical nomenclature ; see 125. 
Abbreviated C a C~a t e. 

142- Quick lime, that is, calcium oxide, absorbs water 
with great avidity, evolving much heat thereby, precisely 
as in the case of potassium oxide (139). 

The resulting calcium h y d r a t e is commonly 
known as slacked lime. It is but sparingly 
soluble in water ; one cubic centimeter of water (1 gr.) 
dissolving only 5 /4 mgr. of the hydrate. The clear solu- 
tion resulting is called lime water; it is a solution 
of calcium hydrate.* 

143. Barium hydrate and strontium 
hydrate are obtained in a similar manner from their 
carbonates, which also occur as minerals. But these two 
hydrates are much more soluble in water, than calcium 
hydrate. 

144. No other hydrates can be obtained by the means 
now described ; because all other oxides are insoluble in 
water. For example, a short piece of magnesium wire 
burnt gives magnesium oxide ; but this is not dissolved 
in water ; after filtration, the oxide is found unchanged 
on the filter paper (El. Phys., 154). 

We shall afterwards learn how the hydrates of these in- 
soluble oxides can be prepared, by making use of the fact 
that these hydrates are also insoluble in water. 

145. The soluble hydrates, especially those of the ka- 
loids, are often spoken of as A 1 k a 1 i e s, also caustic 
alkalies. All hydrates are frequently termed bases. 



# The stadent may intensely heat about half a decigram of calcite on platinum 
foil by means of the blow-pipe directed obliquely against the foil from below up- 
wards. He will then obtain burnt lime, which when cold will hiss with a minute 
drop of water, and form slacked lime, producing a blue spot upon red litmus paper. 
By adding sufficient water to it in a test tube, lime water is obtained. 

If the calcite is carefully weighed, on the foil, before and alter ignition, it will ho 
found to lose nearly one-half of its weight by ignition. Hence nearly one-half of 
calcite is carbon dioxide, and somewhat more than one-half is calcium oxide. 

11 



82 Chapter V. 



146. It will be noticed that hydrogen is a component 
element both of the acids and of the bases ; but that in the 
acids hydrogen is electro-positive as compared to the 
metalloid elements S, P, C ; while in the bases hy- 
drogen is electro-negative in reference to the metallic 
elements Ka, Na, Ca, Ba, etc. Accordingly we have the 
following definitions and additional rules in chemical 
nomenclature : 

An acid is a compound containing hy- 
drogen as the electr o-p o s i t i v e element ; usu- 
ally combined with metalloids. 

A base or hydrate is a compound con- 
taining hydrogen as the electr o-n e g a- 
tive element, usually combined with a metal and 
oxygen. 

147. Acids turn blue litmus paper red; bases or hy- 
drates turn red litmus paper blue — but only if these com- 
pounds are soluble in water. Hence'the above difinitions 
embrace many more, compounds than could be recog- 
nized by litmus paper as bases or acids. But between the 
extreme action of potassium hydrate and sulphuric acid 
on the test paper, we have actually many gradations — 
many substances, not acids nor bases according to the defi- 
nition turning the litmus colors. Hence, in the future we 
shall use the terms acid and base exclusively in accord- 
ance with 146. Whether hydrogen is electropositive or 
electronegative in these compounds is decided by elec- 
trolysis (see 105). 

148. Even when bases and acids are mixed, the base 
is found at the electronegative pole, and thus proves itself 
electropositive, while the a c i d , in the same man- 
ner, appears at the positive pole, and thus is electro- 
negative. 

149. In some respects, tincture of cochineal* 

* Cochineal wanned with dilute alcohol and filtered. 



Acids and Bases. 83 



is preferable to litmus paper or litmus solution. For the 
ruby color of the tincture changes to purple by solu- 
ble hydrates, and to orange by acids. One drop of 
the tincture is sufficient to tinge 20 to 50 cc of the solu- 
tions of hydrates or acids. In general, liquids which do 
not change the ruby color of cochineal tincture are said to 
have a neutral reaction; if changed to orange, 
they are said to have an acid reaction; if changed 
to purple, they are said to have an alkaline reac- 
tion.* 

150. If we now carefully add a dilute solution of the 
acid, drop by drop, from a pipette to a cubic centimeter of 
a solution of a hydrate, tinged purple by cochineal tinc- 
ture, we will, after some time, see the color turn ruby- 
red, and by the next drop, to orange. 

"When ruby, the solution was neutral (149), the op- 
posite action of acid and alkali exactly balancing one an- 
other. The number of drops required to produce 
this neutralization will, for the same solution of acid and 
base, be found to be constant. That is, base and 
acid neutralize each other in fixed proportions, 
which are to be determined by experiment. 

It is of course necessary to stir, or better, to shake the 
liquid after the addition of each new drop, in order to dis- 
tribute it evenly through the liquid. Besides, it is often 
advisable to add some water to the cubic centimeter 
of solution to be neutralized. f 

*The same terms are also applied to the corresponding deportment towards 
litmus paper or litmus solution. 

f Instead of counting the number of drops, it is better to measure the vol" 
ume of acid used, if an apparatus for this purpose be at service. Mohr's Bu- 
rette is the best apparatus for accurately measuring the amount of acid used. It 
consists of a wide glass tube, graduated to cubic centimeters and tenths (or fifths), 
drawn out to a narrow tube below. On this a rubber tube fits, kept closed by a brass 
spring clamp; the lower end of the rubber is provided with a glass jet. Fig. 18. 

The burette is supported vertically, filled with acid up to the zero mark. It is 
sufficiently large for students' use if it holds 25 cc. 

The vessel (beaker) containing the alkali is held in the right hand, and stirred 
(describing a horizontal circle with the right hand). The buttons of the spring 



84 Chapt 



er 



151. If the solution resulting by the neutralization of, 
for example, potassium hydrate by hydrogen sulphate, is 
properly- concentrated and left to cool, fine crystals will 
form, identic with the crystals of potassium sul. 
p hat e described in El. Phys. 182. 

If the evaporation be continued till dryness, the same 
substance, but imperfectly crystallized, will remain. Noth- 
ing but water will pass off, proved, if required, by evap- 
oration of the solution in a small distilling apparatus. 

Accordingly, we find that potassium hydrate and hydro- 
gen sulphate give, upon neutralization, potassium sulphate 
and water. The water may therefore be considered as 
hydogen hydrate, or the ternary H, O, and H ; this is in 
accordance with the fact, that the volume of hydrogen is 
twice as great as the volume of oxygen (102). 

Abbreviated by the use of the symbols, the above chem- 
ical process of neutralization may be written — 

Ka H-ate + H S-ate = Ka S-ate + H H-ate 

That is, the electropositives, Ka and H, have changed 
place; this is called double decomposition. 

152. The mutual chemical action of compounds upon 
one another is usually called a reaction. It conduces 
to clearness if the reaction is represented in diagrams. 
The simplest representation of the reaction taking place 
when potassium hydrate (Ka H-ate) is neutralized by hy- 



c lamp are constantly between the thumb and first finger of the left: a gentle pres 
sure will cause one drop to flow out. 

When the color has changed, read the burette ; it will show the number of cc used 
for neutralization. 

It is best to add another ce of alkali to the beaker, and repeat the neutralization 
Five such experiments will give a mean value very accurate. 

By using two burettes, — one for acid and the other for the base, — these experi- 
ments may be performed with greater rapidity, and base and acid may be alter- 
nately neutralized. This forms also a good lecture experiment. 

The solutions for students' use should contain only about 2 or 3 centigrams of the 
above substances to the cubic centimeter. 

* Until a glass rod, moistened with the solution, becomes covered with a crust of 
crystals soon after being taken out of the solution. 



Acids and Bases. 85 



drogen sulphate (H S-ate) is, according to the preceding: 

* H H-ate 




y Ka S-ate 



On the blackboard, these arrows should be drawn out 
in full. 

153. If additional demonstration is required for this 
mutual decomposition, it may be obtained as follows : — 

A drop of the solution of Ka H-ate remains clear upon 
the addition of a drop of Ba H-ate ; but a drop of solution 
of H S-ate, as well as a drop of the resulting Ka S-ate 
becomes turbid. Hence, the resulting Ka S-ate contains 
the sulphur compound of II S-ate. 

Again : Ka H-ate, on a clear platinum strip (see 27) 
tinges the flame purple. So does the resulting Ka S-ate, 
but not the distillate H H-ate. But the purple flame is 
characteristic of burning Ka. Hence, the resulting Ka 
S-ate does indeed contain the Ka. 

153. Compounds, binaries, or ternaries, not containing 
hydrogen, are called salts. Thus, Ka S-ate, Ca C-ate 
are salts. This completes the nomenclature supplemented 
in 14:6. We unite the terms acid, base, and salt in the 
following scheme : — 



NAME. 


BINARY. 


TERNARY. 


HYDROGEN. 


Acid 


H v-ide 


H v-ate 


Positive. 


Salt 


7i v-ide 


tt v-ate 


None. 


Base 


tt H-ide 


7i H-ate 


Negative. 



154, In the act of neutralization, much heat is usually 
produced, as will have been noticed above. That is, the 
salt (and water) results from double decomposition of acid 
and base, because the latter occupy a higher chemical 



86 Chapter V. 



level. The process in double decomposition is the same 
in kind, as the flowing of water down a slope. 

Inversely, in order to reproduce acid and base from a 
salt, we have to apply an amount of heat (or mechan- 
ical work) equal to that produced in the formation of the 
same salt. The galvanic current is usually the simplest 
and most direct form of mechanical work applicable for 
the reproduction of acid and base irom the salt and water; 
the base appearing at the negative pole, the acid at the 
positive pole. This fact may. be shown by tinging the so- 
lution either with cochineal or litmus (105). 

155. In addition to the above, the following quan- 
titative experiments on combustion may 
be performed by the student : — 

Combustion of carbon. Weight of product of 
combustion (carbon dioxide) per gram of carbon burnt. 
Use apparatus, Fi£. IT, described in 130. Weigh com- 
bustion tube A with charcoal before and after combustion ; 
difference, equals amount of carbon burnt. One decigram 
is quite sufficient if the balance weighs to the centigram 
Use an absorption tube containing coarse fragments of 
pumice, moistened with potassium hydrate, which absorbs 
completely all carbon dioxide passing over it. "Weigh ab- 
sorption tube before and after the experiment; the in- 
crease in weight is the weight of the carbon di- 
oxide produced in combustion. Divide the latter by 
the first weight, and the fraction — 
carbon dioxide 

carbon 
the proportion sought. 

After use, close the glass tubes of the absorption tube 
by minute corks — or the rubber attachments by glass 
rods. 

156. The same experiments may be made with sul- 
phur; but a separate combustion and the absorption 
tube with potassium hydrate should be exclusively re- 
served for the combustion of sulphur. 



Acids and Bases. 87 



157. The products of combustion of any flame may 
also be determined in this manner. Combustibles burn- 
ing with flame contain hydrogen besides the carbon ; 
compare 127. Hence, they produce water, as well 
as carbon dioxide, in combustion. 

Water is absorbed by concentrated 'sulphuric acid, or 
by fused calcium chloride. The apparatus should then be 
arranged thus : The flame burning in a sufficiently wide 
tube (a funnel will do pretty well), attached by a rubber 
tube to the water absorption tube (containing concen- 
trated sulphuric acid or pumice) ; this tube is connected 
with the absorption tube for carbon dioxide (described in 
155); the latter is connected with the aspirator. 

Loss in weight of the candle or lamp gives the amount of 
combustible consumed == A; increase of water absorption 
tube gives amount of water formed = B ; increase of 
carbon dioxide absorption tube gives amount of this gas 
produced = C. 

158. By burning hydrogen in this manner, it has been 
found that 1 of hydrogen gives exactly 9 of water ; also, 
by burning pure carbon, it has been found that 1 of car- 
bon gives exactly n / s of carbon dioxide. Hence, the 
above experiment (157), if made with sufficient care, serves 
as an elementary analysis of the combustible 
used. For an amount of water = B required 1 / 9 B of hy- 
drogen ; the amount C of carbon dioxide required 3 / n C 
of carbon. Hence, in A of the combustible were contained 
1 / g B of hydrogen and 3 /uC of carbon. The remainder is 
put down as oxygen, if the combustible was properly 
dry. 

159. By gently exhaling through these two absorption 
tubes — the water absorption tube nearest the mouth — 
the weight of water and and carbon dioxide exhaled in 
one respiration can be readily determined, if the balance 
weighs to the centigram. If the air passing from the car- 
bon dioxide absorption tube is collected (El. Phys. 127) and 



88 Chapter V. 



measured, we obtain the amount of water and carbon 
dioxide of the exhaled air per litre. 

That the exhaled air contains carbon dioxide is also 
readily proved by passing the exhaled air through lime 
water (136). 

160. In "cosmos ," it will be more completely 
shown that animal life is, chemically, a process of combus- 
tion. If a large volume of atmospheric air — about 10 
litres — is slowly drawn through the above two ab- 
sorption tubes, the amount of water and carbon dioxide in 
the same can be determined by weight. The amount of 
water varies greatly. The amount of carbon dioxide is 
about 4 to 8 volumes (gtfs) in 10,000 volumes of air. This 
is the same as about 6 to 10 grams of carbon dioxide in 
10,000 grams of air. 



CHAPTER VI. 



CHEMICAL PROCESSES. 



I. Reactions. 

161. We shall first consider the chemical processes in 
general, and thereafter add a few examples from the wide 
field of technical chemistry, especially so far as the pro- 
cesses can be carried on by the student with small amounts 
of material. 

We may distinguish three kinds of chemical proces- 
ses ; namely : constructive, exchanging, and 
destructive processes. These may also be designa- 
ted as descending, undulating, and ascend- 
ing processes. 

Synthesis is the simplest descending process, mat- 
ter descending under the evolution of heat from a higher 
to a lower level. Dissociation and electroly- 
sis are simple ascending processes, matter being lifted 
up by the application of heat or mechanical force to higher 
levels. Finally, in double decomposition, mat- 
ter does not produce very much heat, nor revolve very 
much ; such processes may therefore be considered as un- 
dulating. 

Synthesis is also constructive, building up more 
complex forms of matter from less complex materials ; car- 
bon and oxygen uniting, bring the resulting more complex 
material carbon dioxide to occupy a lower level (98). In 
like manner, the ascending processes are destructive, 

in regard to the constitution of the materials ; the more 
12 



90 Chemical Processes. 



complex mercuric oxide is destroyed, as by the application 
of heat it rises to a higher level by dissociation into the 
simple substances murcury and oxygen. 

162. In synthesis we have always a substance 
electropositive tz in reference to the other substance v 
wherewith it combines. In this process we have — 

7i -|- v = m> + heat 
Example : n = 0, aud v = O, the combustion of carbon 
in oxygen ; then each gram of carbon produces 8,000 
calories of heat, equivalent to 3,434,000 gram-meters of 
mechanical work (compare 47 and 86). 

In dissociation we have the reverse : — 

n v + beat = n + v 
If the above carbon dioxide is to be decomposed into its 
elements, it has to be passed through a narrow platinum 
tube intensely heated. Instead of heat, we can use 
any other mechanical force, such as electricity — 

tzv -f- electricity = tt -\- v 
This constitutes electrolysis ; for an example, see the de- 
composition of water (102). 

163. Undulating or exchanging processes 
take place between two substances of which at least one 
is not an element. These processes are more commonly 
termed chemical reactions. We distinguish, ac- 
cording to the above, especially two reactions ; namely : 
those between an element and a compound, and those be- 
tween two compounds. 

Reactions between any element R and any compound tz v 
are called substitutions, if R takes the place of one 
of the elements of the compound. The element takes the 
place of either it or v i according as R is either relatively 
positive or negative. The general formula for these jeac- 
tions are : — 

7r y -f 7tv = 7? v -f 7t =b heat. R = 7tf positive 
v + tzv = v'R v -f v ± heat. R = v y negative 



Chapter VI. 91 



Reactions between two compounds tzv and tf j/ are 
termed double decompositions, and may be 
represented by — 

% v -t{- t£ y v = 7r j/ 4- ^'V-± heat. 

Here we write zh heat, because in some reactions 
heat is produced, in others, heat is required. Of course, 
heat may be replaced by its equivalent in mechanical 
work (see 80). 

164. Quite frequently several of these processes are 
going on at the same time in the same vessel. Such pro- 
cesses may be termed complex processes. 

Many of the great staples, now necessities of life, are 
the result of a complex process, so far as they re- 
sult from a series of processes carried on, one after the 
other, in a chemical laboratory. 

In this sense, animal and vegetable life are complex 
processes ; however, we shall, in " Cosmos," learn that 
the vegetable processes are ascending or constructive, 
while the animal processes are descending or destructive. 

165. The amount of heat evolved or consumed in 
these varied processes can be determined by means of the 
calorimeter (see 46). The work of determining these 
quantities is now carried on with great diligence in various 
quarters. The fixed proportions in weight obtaining in 
these processes between the different materials have al- 
ready, in general, been determined. See 182. Both the 
quantitative determinations in regard to mass (weight) 
and motion (heat or force) must be left for considera- 
tion in the Principles of Chemistry. 

We shall now proceed to the consideration of individual 
examples of these processes. 



II. Synthesis. 



166. Numerous examples of synthesis have already 
been given in the preceding, especially the combustion of 
certain elements (H, P, S, C, Ka), and the uniting of the 



92 Chemical Processes. 



oxides produced with water (129, a. f). See, also, the syn- 
thesis of mercuric iodide, 101. 

Zinc is burnt on a large scale in furnaces ; the resulting 
zinc oxide (flowers of zinc) is used as a paint, under the 
name of zinc white. Lead oxide is also manufac- 
tured by burning metallic lead ; the most common is the 
yellowish litharge. By continued exposure to the air 
at high temperatures, litharge takes up more oxygen, ard 
becomes red lead. 

The student may prepare these oxides by heating a 
small quantity (1 cgr.) of the metals in charcoal, on the 
blow-pipe flame. Observe the changing colors of zinc ox- 
ide upon repeated heating and cooling. Also add a drop 
of cobalt solution to the zinc incrustation, and ignite again ; 
the green pigment resulting from the synthesis of zinc ox- 
ide and cobalt oxide is used as a green paint. 

167. Many oxides are formed by an indirect syn- 
thesis, two or more combined oxidable elements being 
oxidized at the same time. Thus, by the combustion of 
our common combustibles, the oxides of hydrogen (water) 
and carbon are formed at the same time. Compare 157. 

In the common metallurgical process, called roast- 
ing, oxides are formed in the same manner. Common 
pyrite (El. Phys., 165) intensely heated in a glass tube, 
open at both ends, (28) yields sulphur dioxide (see 133), 
and a red oxide of iron.* Hence, pyrite contains 
iron and sulphur ; it is iron di sulphide. Immense 
quantities of pyrite are thus roasted in furnaces, to manu- 
facture sulphuric acid (see 135). 

The white arsenical pyrite, heated in the same 
manner, yields, besides the iron oxide and some gaseous 
sulphur dioxide, also much of a white sublimate of 
arsenious oxide, commonly called white arsenic, 
or ratsbane. On a large scale this oxide is manufactured 

* From this oxide the metallic iron is extracted, by heating a mixture of the oxide 
with soda on charcoal in the reducing blow-pipe flame. 



Chapter VI. 93 



by burning the arsenical pyrite (commonly called mis- 
pickel) in a furnace, to which a series of chambers is 
attached for the deposition of the white arsenic, while the 
sulphur dioxide escapes into the air.* Accordingly, mis- 
pickel contains iron, sulphur, and arsenic. Most of the 
ores containing sulphur and arsenic have to be freed from 
these elements by roasting before the metal can be ex- 
tracted. 

168. At times, only some one of the elements is oxi- 
dized in such indirect combustion. Thus, most of the 
lead, as smelted from its ore, contains a small quantity of 
silver. Since the lead is oxidable (combustible), but 
the silver not, the latter will remain if the lead is burnt 
away. Argentiferous silver is heated intensely in a strong 
current of air; the lead oxide formed fuses, partly 
runs off, and partly soaks into the porous hearth ; finally, 
the pure silver remains. This metallurgical process is 
called cupellation. 

By heating a small piece (5 cgr.) of richly argentiferous 
lead on a bone-ash cupel in the oxidizing flame of the 
blow-pipe, the student may, on a small scale, imitate the 
process of cupellation. f The blow-pipe assay of silver 
consists in the cupellation of the argentiferous lead ob- 
tained from the alloy or mineral by scorification.* 

169. Many iodides, bromides, chlorides, sulphides, etc., 
are also obtained by direct synthesis from the elements. 
See 101. 

By fusing metals with a proper proportion of sulphur, 
many sulphides may be readily obtained ; especially Fe, 



*It will be noticed that the apparatus used for manufacturing purposes is exactly 
represented in its different parts by the different portions of the glass tube above 
used. 

f White burnt bone pulverized, and the fine bone-ash, either packed firm in a cavi- 
ty of the charcoal, or better, formed in Plattner's cupel-iron. 

♦About 2 cgr. silver coin alloy fuse together with 1 dgr. pure lead (test lead). The 
resulting globule cover with about an equal portion of borax; heat in oxidizing 
flame on charcoal until but a small metallic globule remains. This globule is cu- 
pelled. 



94 Chemical Processes. 



Cu, Sn, As. By heating charcoal in a tube red hot, and 
passing vapors of sulphur over it, carbon bisulphide 
is formed, and may be obtained in the liquid form bv con- 
densing its vapor. Carbon burns with sulphur precisely 
as with oxygen. 

170. The black iron sulphide, properly called fer- 
rous sulphide, is obtained by fusing a mixture of 1 
sulphur and 1-J iron. It is much used in the laboratory, 
because with acids it evolves the useful sulphuretted hy- 
drogen gas. The student may prepare a small quantity 
of ferrous sulphide by fusing about 5 cgr. of the mixture 
in a closed glass tube. By dipping the hot extremity of 
the tube into water in a glass, the tube cracks, and the 
sulphide may be taken out. If put into water, and a 
drop of sulphuric acid is added, the sulphide will evolve 
the sulphuretted hydrogen gas, easily recognized by its 
offensive odor (of rotten eggs). 

III. Substitution. 

171. The general formula of substitution has already 
been given in 163. We may therefore pass directly to 
the exemplification of some of the kinds of substitution 
most commonly practiced. 

172. Many electropositives (especially metals) may be 
substituted for hydrogen in acids, by dissolution. 
Thus, the kaloids and calcoids displace hydrogen, even in 
water at common temperatures : 

Ka -f- H H-ate give Ka H-ate -f H 
The metals Mg, Zn, Fe, require a dilute acid in 
order to displace hydrogen, especially dilute sulphuric or 
hydrochloric or nitric acids : 

R + H S-ate — R S-ate H 
The metals Cu, Hg, Ag, do not displace the electropositive 
H in dilute acids ; but concentrated sulphuric or 
nitric acid are dissociated, especially upon heating, 
and yield the corresponding sulphate or nitrate, together 
with sulphur dioxide or nitrogen dioxide — both gases 



Chapter VI. 95 



readily recognized by their pungent and peculiar odor. 
The reactions may be expressed thus : 

R + 2 H S-ate = R S-ate + water S dioxide. 
R -f- 2 H N-ate = R N-ate + water N dioxide. 

The nitrogen dioxide gas oxidizes in contact with the air 
to the characteristic red vapors always observed when 
nitric acid is dissociated. 

Gold and platinum are not dissolved by any of the 
above acids, taken singly; but they are dissolved, when 
heated, in a mixture of nitric and hydrochloric acids. This 
mixture is called aqua regise. It yields the chlorides 
of the above metals. 

173. Accordingly, we distinguish the following f ou r 
grades of solubility for metals : — 

1. Sol. in water : Kaloids, K& and X&. 

2. Sol. in dil. acids : Mg, Zn (Pb), Fe. 

3. Sol. in cone, sulphuric or nitric acids : Cu, Hg, Ag. 

4. Insol. in single acids, sol. in aq. reg. : An, Pt. 
Also, Sn and Sb are oxidized by strong nitric acid, but 

not dissolved. 

For students' practice, about one centigram of either of 
these metals may be dissolved as indicated. Thus, may 
be prepared : — 

In crystals: Hydrated Mg S-ate (epsom salt, El. 
Phys., 185) ; hydrated Fe S-ate (green vitriol) ; Pb 
N-ate ; Hg-ic K-ate (by heating) ; Ag JS-ate. 

Not readily crystallized: Mg, Zn, Fe, Au, 
Pt, chlorides. 

Always observe the gas evolved ; verify that from d i - 
lute acids, H is evolved; from concentrated N-acid, red 
fumes ; from concentrated S-acid, sulphur dioxide. Use 
water-bath, except for the salts of Au, Pt, when the sand- 
bath is advisable. Never use more than 2 cgr. of metal; 
add acid, drop b} T drop, as required, never adding a new 
drop until called for by the cessation of the reactions, and 



96 Chemical Processes. 

the continued presence of the metal. From the crystals 
formed, try to reproduce the metal in the reducing flame 
on charcoal before the blow-pipe. See 175. 

174. From the preceding, it will appear that the or- 
der of solubility of the principal metals is as follows : 

most Ka, Na, Mg, Zn, Fe, Pb, Cu, Hg, Ag, Au, Pt, least 

If, therefore, any of these metals is placed in the solu- 
tion of any of the metals less soluble, the latter will be 
r e d u c e;d . Thus, Ag thrown into Au solution, will re- 
duce the gold : 

Ag -f Au Solution = Au + Ag Solution 
The most common case is — 

Fe -1- Cu Solution = Cu + Fe Solution. 
This reaction you can verify by throwing any fragment of 
iron into a solution of copper ; you will soon see the blue 
color of the copper solution fade and change into the green 
color of iron solutions, while metallic copper separates in 
the shape of the iron, especially if the copper solution was 
dilute. If the copper solution is not dilute and acid, 
the copper separates always as a brown powder, which, 
when pressed by the knife on paper, assumes metallic 
luster. 

A dilute* lead solution, especially of lead acetate, de- 
posits beautiful leaf-like crystals of metallic lead, if a brass 
wire to which a small piece of zinc is attached, is immersed 
into the solution, and the latter stoppered. A few cubic 
centimeters of solution in a minute vial are sufficient. 
This arborescent growth of lead crystals is often called the 
lead tree. 

Pb Acetate -}- Zn give Zn Acetate + Pb. 

All these reductions of the less soluble metals from their 
solution are termed reductions in the wet way. 

175. In the dry way, many metals can also readily 
be reduced from their compounds, by means of metals or 
metalloids more combustible. 

•Containing but 1 or 2 cgr. in each cc. Solution cleared by acetic acid. 



Chemical Processes. 97 



Of all the elements, carbon and hydrogen are the more 
combustible ones. Hence, carbon and hydrogen are, in 
high temperatures, powerful reducing agents. The cheap- 
ness of coal makes its application for the reduction of 
metals very nearly universal and exclusive. 

Thus, all iron ores — at least, after roasting — are iron 
oxides. They are, in high furnaces, mixed with 
coal. The coal burns, partly at the expense of the oxygen 
of the iron oxide, which thus becomes reduced to metallic 
iron.* In like manner, zinc, lead, copper, are obtained 
from corresponding ores. 

The student should ■ practice such reductions by the 
blow-pipe on charcoal. A little soda is mixed with the 
ore, to facilitate the reduction. See 95 ; also, 25. 

Ey passing hydrogen over the oxides of copper or 
iron, the oxide is also reduced to the metallic condition 
under the formation of water; thus: 

Cu O-ide & H give Cu & H O-ide (water). 

This experiment may also be performed by the student ; 
the oxide to be reduced should be gently heated in a glass 
tube while the hydrogen gas is passed over it. For cau- 
tion, 103. 

176. Iron combines more readily with sulphur than 
lead, especially in higher temperatures. Hence, lead can 
be smelted from its ore — galena — ( — lead sulphide), by 
throwing iron into the fused ore. Thus : 

Pb S-ide & Fe gives Fe S-ide & Pb. 
In a like manner, antimony is smelted from its ore, Sb 
S-ide. 

These processes are readily exemplified by means of 
minute quantities heated in the glass tubes by the blow- 
pipe. 

177. The substitution by means of an electronegative 
element is not so common as the above. 

""•Containing from 4 to 5 per cent, carbon, thus constituting pig iron, or cast iron- 
By burning the carbon out (Bessemer process, also, puddling process), steel (1 to 2 
per cent, carbon) and wrought iron (% per cent, carbon) Is obtained. 

13 



98 Chapter VI 



The simplest case is the substitution of the chloroids, 
one for another. Bromine expels iodine ; chlorine expels 
either iodine or bromine ; thus : 

Br & n Io-ide = n Br-ide & Io 
CI & n Br-ide = n Cl-ide & Br 
CI & it Io-ide = 7t Cl-ide & Io 

The student should practice these substitutions in the 
following manner. To a drop of the iodide, or bromide 
solution in the test-tube, add about 0.5cc. of water ; then 
two or three drops of carbon bisulphide, or chloroform ; 
finally, a small drop of dilute chlorine water.* The chlo- 
rine displaces the Io or Br, the latter being not very solu- 
ble in water, but readily soluble in the chloroform or car- 
bon bisulphide, and are, upon shaking, transferred 
to the latter, which becomes tinged by the iodine (red) or 
bromine (reddish yellow) dissolved. 

178. Chlorine also frequently displaces oxygen ; thus: 
it O-ide + CI — n Cl-ide + O. 
If chlorine water is exposed to sunlight it is decomposed, 
yielding hydrochloric acid ; thus : 

H O-de + CI = H Cl-ide + O. 
Therefore, chlorine is a powerfully oxidiz- 
ing agent, so that it is eminently applicable for disin- 
fecting and bleaching purposes. The manufacture of 
bleaching powder (chloride of lime) and of bleach- 
ing solution (chloride of soda) depends upon this proper- 
ty. The chlorine gas, brought into contact with the calci- 
um hydrate (slacked lime), yields chloride of lime ; if 
passed into dilute sodium hydrate solution, the so-called 
Labarraque's solution of chloride of soda re- 
sults. The process is not a simple substitution, but com- 
plicated by double decomposition ; hence, it is not proper 
here to give further details. The resulting bleaching com- 



* Chlorine absorbed in water; this solution keeps only in bottles covered with 
black paper; see 178. 



Chemical Processes. 



99 



pounds contain the chlorine in a more permanent form 
than the chlorine water; but the slightest amount of acid 
will set the chlorine free again. 

On account of the deliterious effect of chlorine on the 
respiratory organs, these experiments should not be made 
by students in the general laboratory. 

179. The oxidizing action of chlorine is also used for 
the manufacture of potassium chlorate. Into a 
concentrated, warm solution of potassium hydrate, chlorine 
gas is passed ; soon crystals of potassium chlorate separate, 
while in the liquid remains potassium chloride. The pro- 
cess is rather intricate ; the oxygen of the hydrate is 
concentrated in the chlorate, while the chloride retains 
the greater part of the potassium, and the hydrogen yields 
water. 

180. By the oxidizing action of chlorine (or chlorine 
water) tt-ous solutions may be converted into 7r-ic solu- 
tions. Compare 125. 

Green vitriol gives a pale green solution of ferrous 
sulphate (5 cgr. in 1 cc. water suffice). Chlorine water 
added hereto gives a faint yellow solution of f e r r i c sul- 
phate, especially upon gently heating the same. 

By a few precipitations (see 182) these two salts maybe 
more readily distinguished. To a d r o p of the solution, 
placed on a glass plate, a d r o p of the re-agent is added ; 
the precipitate stated below will then be observed : 





SOLUTION. 


RE-AQ-ENT. 


Ferrous. 


Ferric. 


Am Hydrate 

Ka Cyanoferrate 
Ka Cyaniferrate 


Whitish, changes to 
green and brown, 
no pr. 
blue pr. 


brown, 
blue pr. 
no pr. 



Potassium permanganate is also a powerful 
oxidizer in the wet way. It changes ferrous salts imme- 
diately into ferric salts. Each drop of the permanganate 



100 Chapter VI. 



solution loses its beautiful purple color immediately in the 
ferrous solution ; but when all of the ferrous salt has thus 
been oxidized to ferric salt, the next drop of permanganate 
added tinges the entire iron solution purple. To prevent 
the precipitation of some of the iron compound, it is best 
to add a few drops of pure sulphuric acid before adding 
the permanganate. 

By means of a standard permanganate solution, the 
amount of iron in a ferrous solution can therefore be most 
readily determined by noting the volume of permanganate 
solution consumed. 

181. Oxygen can replace sulphur. If sulphuretted hy- 
drogen (see 170) is passed into common water — which 
always contains some air — the resulting liquid will soon 
become turbid, from the separation of minute particles of 
sulphur. The substitution taking place is 

H S-ide + = H O-ide + 8. 

The same separation of sulphur constantly takes place 
near sulphur springs ; the oxygen of the air taking the 
place of the sulphur in the hydrogen sulphide water. 
Hence, if sulphuretted hydrogen, i.e.: hydrogen sul- 
phide, is to keep in solution in water, the water should, 
by boiling, be freed from all air before the gas is passed 
into it. 

For the same reason, hydrogen sulphide in solution is a 
reducing agent ; ferric solutions are reduced to ferrous so- 
lutions under the separation of water, the additional oxy- 
gen being taken from the ferric compound. Chromates 
are also reduced by hydrogen sulphide, the yellow color 
changing to green thereby. 

182. By careful quantitative determinations, it 
has been found that the elements replace one another in 
fixed, invariable proportions. Thus : to displace one gram 
of hydrogen by potassium (see 172), requires 39 grams of 
potassium ; 23 grams of sodium are required to displace 1 
gram of hydrogen ; hence, 23 grams of sodium, or 39' 



Chemical Processes. 101 



grams of potassium are equivalent tol gram of hy- 
drogen. 

By the substitution of iron for copper, etc. (see 174), it 
is found that 56 grams of iron are equivalent to 63.4 grams 
of copper ; each of these quantities being equivalent to 2 
grams of hydrogen, because 63.4 grams of copper can be 
replaced by 2 grams of hydrogen. 

In the "Principles of Chemistry" these re- 
lations will be fully investigated. Here it must be suffi- 
cient to give an alphabetical list of the symbols of the ele- 
ments, together with the so-called atomic weight 
of the element, determined mainly by ascertaining the 
relative quantity of the elements in substitution. The 
atomic weight of hydrogen is taken as unity, or H =^= 1 ; 
the weight of the smallest possible particle or 
atom of hydrogen is thus taken as the unit of the atomic 
weight. Hence, Ka — 39, signifies that one of the 
atoms of potassium weighs as much as 39 atoms of hydro- 
gen. 

183. Table of Atomic Weights of the Elements : 



Ag 


108 


CI 


35.5 


Li 


7 


Eli 


104 


Al 


27.4 


Co 


60 


Mg 


24 


S 


32 


As 


75 


Cr 


52 


Mn 


55 


Sb 


122 


Au 


197 


Cu 


63.4 


N 


14 


Se 


79.5 


Ba 


137 


Fe 


56 


Na 


23 


Si 


28 


Bi 


210 


Fl 


19 


m 


58 


Sn 


118 


Bo 


11 


H 


1 





16 


Sr 


87.6 


Br 


80 


Hg 


200 


p 


31 


Te 


128 


C 


12 


Ir 


198 


Pb 


207 


Ti 


50 


Ca 


40 


lo 


127 


Pd 


107 


Ur 


120 


Cd 


112 


Ka 


39 


Pt 


197.4 


Zn 


65.2 



184. The quantitative composition of a chemical com- 
pound can now be expressed by a chemical formu- 
1 a, consisting of the symbols of the constituent ele- 
ments, each provided with an index, stating the num- 
ber of atoms of the element contained in each atom of the 
compound. Thus, the chemical formula of water is ILO; 



102 Chapter VI. 



that is, each atom of water consists of two atoms of hydro- 
gen and one atom of oxygen. Hence, by weight, 2 atoms 
= 2 of hydrogen, and one atom = 16 of oxygen, give 
one atom = 2 4- 16 = 18 of water. So, also, Ca0 3 C is 
the chemical formula of calcium carbonate ; for it has been 
found that one atom Ca = 40, and three atoms O 
of 16 or 48, and one atom C = 12, constitute one 
atom of calcium carbonate, which, therefore, weighs 40 -f 
48 -f 12 = 100, or as much as 100 atoms of hydrogen. 

As stated above, the full consideration of this subject, 
and especially the demonstration of the same, 
must be deferred to the principles. The following few ex- 
amples may prove of interest : 

Hydrogen sulphate, H 2 4 S. Silver nitrate, Ag0 3 N. 
Barium chloride, BaCl 2 . Carbon dioxide s C0 2 . Mercuric 
oxide, HgO. Mercuric oxide, HgIo 2 . 

IV. Double Decomposition. 

185. The general formula for double decomposition 
has been given already in 163. Accordingly, if two com- 
pounds 7T v and 7? ]/ both decompose and inter- 
change components, we shall have the new com- 
pounds tz v and ri v\ such a process is called double de- 
composition. 

But when two compounds are mixed, we can, as a rule, 
not readily tell whether double decomposition actually 
takes place or not, unless some of the new 
compounds separate from the mixture. 
Such separation can only consist in volatilization 
or in pre c i p t ation. 

If one of the new compounds is volatile, converted 
into a gas (if necessary, by means of some heat), we have 
a doable decomposition by volatilization 
which may be represented in the following scheme : 



or, 



Double Decomposition. 103 



n „ y ri v volatile ; passes off. 

X 
tt' v j- n \t non-volatile ; remains. 

k v. + rf 1/ give tt 1/ + tt' v 

non-volat. non-volat. volat. 

If one of the new compounds is i n s o 1 u b 1 e, it 
will of course appear in the solid form, separating from 
the solution as fast as produced ; such separation of a solid 
from a liquid we call precipitation, because, as a 
rule, the solid has a greater specific gravity than the solu- 
tion, and therefore sinks to the bottom of the vessel as if 
it had been thrown down (precipitated). 

The general formula for double decomposition 
by precipitation is 

it v yrfv soluble ; remains in solution. 

X 
rf 1/ ytzi/ insoluble ; precipitated. 



or, 



n v + 1? 1/ give n f v + iz v' 

soluble. insol, pr. 



It is of course highly important to observe especially 
the color of the precipitate, also its s o 1 u b i 1 i t y in 
liquids other than the solution in which it formed. It is 
also important to ascertain whether further addition of the 
precipitant redissolves the precipitate formed or not. 

186. To effect a complete separation in double decom- 
position by volatilization, the volatile compound has often 
to be expelled by the application of heat, and collected by 
cooling in a receiver ; in fact, the volatile compound is 
distilled off. Therefore, the double decompositions 
by volatilization are, in such case, also termed double de- 
composition by distillation; or sublimation, 
in case the volatile substance solidifies. 

If the volatile substance is a gas at common tempera- 
tures, no heat will be required. The gas will separate in 



104 Chapter VI. 



bubbles throughout the liquid as soon as mixture takes 
place. Such separation of a gas by double decomposition 
is called an effervescence. 

The properties — especially color and odor — of the vo- 
latile substance should be carefully observed and recorded. 

To effect a complete separation of the solid from the so- 
lution in case of double decomposition by precipitation, 
the entire mass is thrown on a washed filter (El. Phys., 
154), and after the liquid (the filtrate) has passed 
through the filter, the precipitate is washed by water 
(or some other liquid), and the washings running 
through a filter are collected in a separate vessel. 

187. It will already be apparent that these two modes 
of double decomposition are of utmost practical im- 
portance. For any volatile oompound can be pre- 
pared by double decomposition of the first kind ; so, also, 
any solid, by expelling the volatile. Again : any insoluble 
compound can be prepared by precipitation ; and any solu- 
ble compound by precipitating the insoluble from it by 
the same operation. 

Also, in analytical chemistry, these operations are of the 
utmost practical importance, because the separated vola- 
tile or insoluble substance produced by the addition of a 
known compound, in most cases, can be readily identified, 
and thereby make known the other component. 

The following practical examples will tend to make this 
subject better understood. 

188. The more common acids may, in regard to their 
volatility, be arranged in the following order : 

MOST VOLATILE. 

1. H C-ate; dissoc. to carbon dioxide gas. 

2. H S-ide ; gaseous. 

3. H S-ite ; dissoc. to sulphur dioxide gas. 

4. H Cy-ide ; gas — exceedingly poisonous. 

5. H Cl-ide. 

6. H N-ate. 



Double Decomposition. 105 

7. H Acetate. 

8. H S-ate ; the most common. 

9. H P-ate. 

10. H Bo-ate. 

11. H Si-ate; dissociates to silicon dioxide, solid. 

LEAST VOLATILE. 

This is ascertained by heating the acids named. 

189. Accordingly, by means of the most common acid, 
— H S-ate, — we can prepare all the more volatile (pre- 
ceding) acids. The first four require no application of 
heat, because they* are gaseous at common temperature. 
The next three are prepared by the application of heat ; 
i. e., by distillation. The following examples may be 
worked by the student, and written out as in 183 and 184 : 

190. Na C-ate + H S-ate give Ea S-ate + H C-ate ; 
but the H O-ate dissociates into water and carbon dioxide 
gas, which passes off (odorless, effervescence). If calcium 
carbonate is to be used, sulphuric acid will be found to 
work slow, because calcium sulphate is not very soluble ; 
hence, to dissolve Ca C-ate, take hydrochloric acid H 
Cl-ide, or nitric acid H N-ate ; thus : 

Ca C-ate + H Cl-ide give Ca Cl-ide + H C-ate (dissoc*). 
By weighing a light flask, loosely stoppered with cotton, 
and containing dilute hydrochloric acid (1 acid to 3 water), 
throwing into the acid a known amount (ca. 5 dgr.) of 
limestone successively in small pieces, waiting each time 
until the preceding piece is dissolved, also each time 
quickly replacing the cotton stopper to retain the moisture ; 
then the weight of the flask and contents, at the close of 
the experiment, is equal to its original weight plus the 
weight of limestone dissolved less the weight of carbon 
dioxide gas passed off. From these data, , calculate the 
amount a of carbon dioxide gas in one gram of limestone. 



*Or their product of dissociation (see 1 and 3) ; which again, in water, reproduces 
the acid. Compare 134. 

14 



106 Chapter VI 



If you treat pure calcium carbonate, such as calcite frag- 
ments, in this manner, the balance will be calcium oxide. 
Compare 141. 

191. The sulphites deport themselves precisely 
as the carbonates, except that the gas evolved has the odor 
of burning sulphur, because it is sulphur dioxide. For 
experiment, use sodium bisulphite. 

192. By adding a drop of sulphuric acid to the water 
in a test tube containing a few small fragments of iron 
sulphide, the liquid will effervesce; the gas evolved pos- 
sesses the odor of rotten eggs, and thereby is readily rec- 
ognized (170). It is commonly called sulphuretted hy- 
drogen, but its scientific name is hydrogen sulphide, as 
will be seen from the following : 

Fe S-ide + H S-ate give Fe S-ate + fl S-ide. 
See, also, 181. 

193. A cyanide treated in the same manner gives an 
effervescence possessing the odor peculiar to peach blos- 
soms ; this odor is due to the highly poisonous gas evolved, 
which is hydrogen cyanide, commonly called 
hydrocyanic or prussic acid. 

Ka Cy-ide + H S-ate give Ka S-ate -\- H Cy-ide. 
The student should operate only with exceeding minute 
quantities.* 

194. Hydrogen chloride is evolved from sodium chlo- 
ride (common salt) and sulphuric acid ; a gentle heat may 
be applied. The gas is usually collected in water, and 
the aqueous solution resulting is commonly called hydro- 
chloric acid. 

Na Cl-ide -f H S-ate give Na S-ate -f H Cl-ide. 
The common, impure acid of the shops is called m u - 
riat i c acid. 

195. Nitric acid is distilled from sodium nitrate (Chili 
saltpeter) and sulphuric acid. 

*In such case, but very little water should be used, because the gas is rather aolu- 
ble in water. 



Double Decomposition. 1U7 



!Na N-ate -f H S-ate give Ma S-ate + H JST-ate. 

The pure potassium nitrate (saltpeter) gives a purer 
product. 

The common impure nitric acid is also called aqua 
f o r t i s. 

196. Acetic acid is commonly distilled from lead acet- 
ate (sugar of lead) and sulphuric acid : 

Pb Acetate -f H S-ate give Pb S-ate -f H Acetate. 

A small quantity of the acetate heated in the test tube 
with a drop of dilute sulphuric acid, will yield the acid in 
sufficient quantity to be recognized by its odor. 

197. The acids less volatile than sulphuric can, of 
course, not be prepared by sulphuric acid. But these 
acids are often used to produce the salts, by heating 
the acid with the corresponding sulphate. 

Thus, copper phosphate will be left, if copper sulphate 
is sufficiently heated (ignited) with phosphoric acid : 
Cu S-ate -f- P-ate give Cu P-ate -f- H S-ate. 
It requires a temperature of more than 200° to expel the 
hydrogen sulphate; the acid dissociates, forming 
white fumes. Since these fumes are exceedingly corrosive, 
the experiment should be made with minute quantities on 
the foil. 

198. The silicate of any metal is prepared by igniting 
with silicic acid the salt of the same metal containing any 
volatile acid ; such are, according to 188, the carbonate, 
sulphide, sulphite, etc., until sulphate, inclusive. 

Cu S-ate -f- IT Si-ate give Cu Si-ate + H S-ate. 
But since silicic acid dissociates into water and silicon di- 
oxide at a low temperature, the latter may be used instead 
of the acid. Sand is a common form of impure silicon di- 
oxide (silica). 

199. The silicates most extensively manufactured are 
water-glass and glass. 

Water-glass is potassium or sodium silicate ; obtained 
by fusing the corresponding carbonates with silica. 



108 Chapter VI. 

Common glass is double silicate of sodium and calci- 
um, obtained by fusing soda (= sodium carbonate), lime- 
stone (= calcium carbonate), and silica together. But 
many other varieties of glass are in use. Flint glass 
is more lustrous, heavier, and less hard than other glasses, 
because it contains some lead oxide. 

These silicates may be prepared by the student as beads 
on the platinum wire. The flint glass bead should be 
fused on charcoal, because it is liable to destroy the pla- 
tinum wire. 

200. Fluxing is the fusing of an insoluble com- 
pound with sodium or potassium carbonate; the resulting 
flux can be dissolved. 

For example : barium sulphate is insoluble in all acids. 
When fused with potassium carbonate on the foil, a dou- 
ble decomposition takes place ; thus : 

Ba S-ate -f- Ka C-ate give Ba C-ate -f Ka S-ate. 
For when the foil is boiled with water, a solution is ob- 
tained containing Ka S-ate together with the excess of Ka 
C-ate used. The residue insoluble in water is Ba C-ate 5 
and dissolves with odorless effervescence in dilute hydro- 
chloric acid. 

This operation is much used in chemistry. 

201. Many other compounds are prepared by double 
decomposition in higher temperatures. We shall here 
mention only two examples. 

Mercuric chloride, commonly called corrosive 
sublimate, is volatile; hence, it may be prepared by heat- 
ing a small quantity of any chloride with any mercuric 
salt in a small tube. The resulting mercuric chloride will 
deposite as a white sublimate on the colder parts of the 
tube ; hence its popular name. It is a deadly poison. 
Hg-ic S-ate -f Na Cl-ide give ISTa S-ate + Hg-ic Cl-ide. 

202.. The volatile base ammonium hydrate (140) is 
prepared by heating any ammonium salt with any hydrate. 

The student may add a drop of potassium hydrate to a 



Double Decomposition. 109 



minute quantity of any ammonium compound (Am v-ate) 
in a test tube ; he will then recognize the ammonia 
gas resulting from the dissociation (140) of the Am H-ate 
produced by its pungent odor, and by producing white 
fumes with a drop of a volatile acid brought near on a 
glass rod, or by turning moistened red litmus'paper blue 
when held in the tube, but above the liquid. 

Am v-ate -f- Ka H-ate give Ka v-ate -f- Am H-ate. 
The Am H-ate dissociates, as stated, into ammonia gas 
and water. 

203. Double decomposition by precipitation (184) en- 
ables us to prepare insoluble compounds. To be able to 
apply this method, we should first learn which compounds 
are soluble, and which are insoluble (in water, understood). 
The following will be verified by subsequent experiments, 
but should be carefully committed to memory : 

1. Soluble are (almost) all salts of the k a 1 o i d s Ka, 
]Na, Am, and hydrogen; also (almost) all nitrates, 
chlorates, acetates. 

2. Insoluble are all carbonates, phosphates, 
oxalates, except those of the kaloids ; all sulphides, 
oxides, and hydrates, except those of the kaloids 
and calcoids. 

3. Insoluble are the sulphates of the calcoids 
(Ca, Sr, Ba,) and lead (Pb). 

4. Ag, Pb, and Hg-ous chloride and iodide 
are insoluble ; also, Hg-ic iodide. 

204, For practice, the student should verify the 
above as far as convenience and time admit. Two modes 
of experimentation should be used alternately ; first, the 
student should investigate the solubility of any given 
negative, such as the sulphates, chlorides, etc. ; sec- 
ondly, the student should investigate the solubility of the 
different salts of the same electropositive, such as lead, 
silver, etc. 



110 Chapter VI. 



Only one drop of the solutions is required, taken by 
means of a tube-pipette from the small reagent flask, Fig. 
19, of about 15 cc. capacity. By means of cotton tied 
around the pipette, the bottle is quite sufficiently closed ; 
only bottles containing corrosive acids require a piece of 
rubber tubing around the pipette. 

The result may be observed either in test tubes, or on a 
glass plate ; the latter method is the most convenient, ex- 
cept in cases when heat or additional solvents are to be 
used. The glass ware used should, of course, be clean ; 
the plate should also be dry. All glass ware should be 
carefully cleaned before it is returned. 

205. If the first method is used, and if the student is 
to verify the solubility of the compounds of the same 
negative, he receives a flask containing the potas- 
sium or sodium salt of this negative, and add6 a drop 
from this to a drop from each of the solutions of Ca, Ba ; 
Mg, Zn, Pb ; Hg-ous, Hg-ic ; Cu, Ag ; Am, Fe-ous, Ni, 
Co ; Al, Fe-ic, O-ic, Sn, As, Sb, Bi ; each contained in 
a separate flask, each provided with pipette and cotton 
stopper. Also, a bottle containing dilute nitric acid. 

The results are carefully entered in the journal ; thus : 



SOLUBILITY OF . . V . 



Solution of v used : 



Sol. Of 77. 


Eesult. 


Ka N-ate 




Ba N-ate 









The result should be stated concisely, but fully : 
whether precipitate forms, what appearance the same has, 
what color; also, whether soluble in dilute nitric acid, etc. 
The card or laboratory label accompanying each set will 
give any further special information required. It will be 
understood that a precipitate forms only if the substance 
is insoluble. 



. Double Decomposition. Ill 

The reaction should be written out as exemplified in 
184, in all cases where a precipitate forms. 

206. The verification of the solubilities of the different 
compounds of the same electropositive (metal) is 
performed in the same manner. In this case, the one so- 
lution of the electropositive (usually nitrate) is accompa- 
nied with a set of the solutions of the Ka or JSTa salts of 
the principal acids named ; thus : sulphate, chromate, 
phosphate, borate, oxalate ; the hydrate, sulphide, chloride 
iodide, cyanide (?), cyanoferrate, cyaniferrate. 

Otherwise, the work is precisely as in 205. 

207. The student may, for 206, prepare the solution 
himself from the metal; only about 2 cgr. of metal is re- 
quired. See 173. 

It is also well to repeat some of the precipitations in a 
test tube, to filter through a minute filter inserted (without 
the aid of a funnel) in another test tube, to wash some, 
and finally to take the precipitate (with lowest part of 
filter) and heat it either alone or with soda on charcoal in 
the inner flame, in order to reproduce the metal (175). 

By working several series of these simple exercises, the 
student will not only have become familiar with the de- 
portment of the substances he handled, but also be able 
to understand many of the processes of chemical technics. 
He will furthermore comprehend by what means the pres- 
ence or absence of the different elements in any given 
substance can be established, and often the amount quan- 
titatively determined. 

208. The amount of chlorine in any solution can 
thus readily be determined by completely precipitating the 
same with a silver solution (silver nitrate) ; for silver chlo- 
ride is insoluble in water and in acids (203, 204). 

7z Cl-ide -f- Ag N-ate give n N-ate -f Ag Cl-ide. 
If a drop of potassium chromate has been added to the chlo- 
ride solution, the liquid will be tinged faintly yellow there- 
rom; as long as chlorine is present, it will be thrown 



112 Chapter VI 



down by the silver solution as white silver chloride ; but 
after all chlorine has been precipitated, the silver solution 
will form silver chromate, which is recognized by 
its red color. Hence, we know when the chlorine is 
all precipitated by the appearance of this red color. 

A solution containing 3.042 mgr. silver in the cubic 
centimeter precipitates 1 mgr. chlorine by each cubic cen- 
timeter. 

The student may determine the amount of chlorine in 
given salt solutions in this manner, using aMohr's burette 
(see 150). The silver chloride produced must be returned 
to the teacher. 

V. Complex Processes. 

209. The processes of synthesis, substitution, and dou- 
ble decomposition are frequently combined, and again, at 
other times, are associated with dissociation or electrolysis. 
In larger and more advanced works on chemistry, many 
such complex chemical processes are described. 

210. Such complex processes are especially frequent 
in the vital processes of plants and animals. In the sub- 
stance of these living beings, a great multitude of different 
serial compounds have been discovered, and infinitely 
more have been artificially obtained from them by chem- 
ical processes. 

A few hints concerning the compounds occurring, and 
the processes whereby they have been transformed in the 
laboratory must be sufficient in these elements. 

211. Vastly predominant in plants are the so-called 
carbohydrates, composed of carbon, hydrogen, and 
oxygen, the last two in the proportion in which they form 
water (compare 158). Woody fibre, starch, gum> and the 
different kinds of sugar belong to this group of compounds. 

212. In the sweet fruits of many plants the variety of 
sugar called grape sugar occurs ; especially, also, in 
the ripe grape of the vine. When grape sugar solution is 






Complex Processes. 113 



mixed with a little yeast, fermentation sets in ; the 
juice of the grape contains a natural ferment, which soon 
causes the fermentation of the must. 

The process of fermentation is a peculiar disin- 
tegration of grape sugar into carbon dioxide and alcohol. 
The first* passes into the air ; the latter can be separated 
by distillation. In the fermented must, called wine, the 
alcohol seems, however, not to be free, but combined in a 
very peculiar manner to the other manifold constituents. 

213. Alcohol, obtained as just stated, constitutes the 
basis of organic chemistry. Innumerable compounds have 
been formed from it. 

Slowly oxidized, alcohol becomes acetic acid; the 
impure and dilute article is the familiar vinegar. 

Treated with chlorine, alcohol yields the highly import- 
ant chloral. Treated with chlorine and potassa, the 
equally important chloroform results. A liquid con- 
taining alcohol, when heated with a little potassium hy- 
drate and a minute quantity of iodine, gives in a like 
manner, iodoform, which upon cooling, separates in 
beautiful yellow hexagonal crystals (microscopic). 

Alcohol, when mixed with sulphuric acid, yields, upon 
distillation, the well known ether (commonly called sul- 
phuric ether, although it contains no sulphur nor sulpuric 
acid). 

In this manner, thousands of peculiar compounds have 
already been prepared from alcohol. 

Finally, alcohol results by fermentation from all sub- 
stances which contain materials convertible into grape 
sugar ; such materials we have in all the carbohydrates. 
Hence, alcohol is formed during the process of bread-bak- 
ing, etc., etc. 

214. Another class of organic compounds are the nu- 
merous acids found in animals (formic, lactic, etc.) and 
plants (oxalic, citric, malic, tannic, etc., etc). They com- 

•How recognized ? See 136. 

15 



114 Chapter VI. 



bine with mineral bases precisely as the acids described in 
the preceding. 

215. Corresponding to the bases or alkalies, we find 
especially in plants, but also in animals, complex bases' 
usually called alkaloids. Such are morphine, strych- 
nine, nicotine, etc. 

Thus we have strychnine sulphate, strychnine chromate, 
and many other salts. A great many of these alkaloid 
salts are important medicines, although most are poison- 
ous. Strychnine is exceedingly poisonous.* 

216. Complex compounds endowed with, or producing, 
splendid colors are also frequent ; we may here refer to 
litmus and cochineal, used above (129, 149). Of late, 
many of the most brilliant colors have been prepared in 
the laboratory, especially the so-called aniline colors, 
from distillation products of coal tar. 

As an example of beautiful organic colors, the student 
may perform Pettenkofer's test for the acids of the bile. 
To a drop of alcoholic solution of bile add a very little of 
sugar solution and a drop of dilute sulphuric acid ; upon 
gently heating this mixture on the water bath, a beautiful 
purple color will develop. 

217. The albuminous substances constitute a 
group of serial compounds most characteristic of the ani- 
mal body. The white of e^g contains a considerable por- 
tion of very pure albumin; in blood we find f i b r i n e, 
and in milk we have casein. These albuminous bodies 
are essential to the formation of animal tissue, and after 
use as such, leave the body as urea. 



* Strychnine and its compounds, when nearly pure, may he recognized hy the fol- 
lowing test: The white substance is moistened with the least possible amount of 
pure sulphuric acid, and a minute crystal of potassium bichromate added; a beauti- 
fnl bluish purple will develop, which soon changes to purple, then to reddish orange 
and fades. 

The student should, on a watch-glass, receive only one drop of the dilute strych- 
nine solution, and test the white residue which remains after spontaneous evapora- 
tion. 



Complex Processes, 135 

The albuminous bodies consist of carbon, hydrogen, ni- 
trogen, and oxygen, with some sulphur. The latter is in- 
dicated by the odor of fresh boiled eggs (compare 170). 

By elementary analysis (158), the composition of these 
compounds has been found to be, for each one part of hy- 
drogen : 

Albuminous bodies : H=l, 0=8, 0=3, N=2. 
Urea: 13 4 7 

So that urea contains comparatively much more of nitro- 
gen than the albuminous bodies. 

218. These few examples must here suffice to indicate 
that the portion of chemistry here considered constitutes 
but the Elements of Chemistry. The body of 
plants and animals furnishes abundant and much used ma- 
terial for chemical research ; the branches of the science 
termed Animal Chemistry, Physiological 
Chemistry, Agricultural Chemistry, etc., 
treat especially of these subjects. Also, the very process 
of the material life on the globe is successfully being stud- 
ied ; the relation of food to force and heat, — even the 
gaseous products of respiration and perspiration, — is be- 
ing accurately investigated. Many important results have 
already been obtained by these researches. A few of 
these results will find a place in the third volume of these 
elements of physical science, in " Cosmos ; " but the details 
must of course be sought in special treatises. 

219. A careful chemical investigation of the substances 
which constitute the solid crust of the earth has led to the 
science of chemical mineralogy and petro- 
graphy. 

The first elements of mineralogy will be found in the 
next chapter, while the elements of petrography will be 
set forth in the third volume of this course. 

220. Special and full information on the various chem- 
ical manufacturing processes — some of which have been 
simply mentioned in this volume — must also bo sought 



116 Chapter VI. 



for in special treatises on technical chemistry 
and metallurgy. 

Similarly we must refer to analytical chemis- 
try for the methods of determining the composition of 
any given substance ; to systematic chemistry 
for a concise and classified description of the multitude of 
chemical compounds; to theoretical chemistry 
for the laws and principles which thus far have been firmly 
established as governing the processes of chemistry, and 
determining the specific properties of chemical compounds. 

In the second year's course, embracing the Princi- 
ples of Physical Science, we shall, in regard 
to chemistry (Yol. 2), mainly give theoretical and 
systematical chemistry. All the other numerous 
subdivisions of the vast field of chemical science must be 
left as special studies, to be taken up after the 
principles shall have been mastered. 



CHAPTER VII. 



ELEMENTS OP MINERALOGY. 
I. Classification and Determination. 

221. All but the serial compounds are prepared from 
the comparatively few chemical compounds which occur 
native, t. e., in the solid crust of the earth, and are 
called minerals. The minerals necessarily form the 
basis of the great chemical arts, such as the smelting of 
the metals from the ores, the making of glass and pottery. 
The minerals also possess a high purely scientific import- 
ance, because nearly all are found in crystallized speci- 
mens, which exhibit at once the physical, morphological, 
and chemical properties of the chemical compound in a 
beautiful manner. El. Phys., 214. 

For these reasons, we select the minerals or na- 
tive compounds as the most useful material, both 
practically and scientifically, to study a large class of 
chemical compounds, and to learn to distinguish the indi- 
vidual compounds one from the other. Since water and 
air have penetrated much farther into the earth than 
miner or rock drill have ever reached, the minerals are 
almost completely restricted to those compounds which 
are insoluble in water, and not readily oxidized. Only 
where a large portion of the sea was cut off and dried up, 
we find deposits of soluble salts in the earth. 

222. The teacher should thoroughly exemplify 
the terms and descriptions given in this section, by the 
exhibition before the class of about a dozen good (if possi- 
ble, crystallized) large specimens, representing different 
groups of minerals (oxides, sulphides, etc). Thereby the 
students will be enabled to determine minerals 



118 Chapter VII 



given to them in the laboratory practice following. Our 
mode of determination (see 230) compels the students to 
carefully study the description of all minerals repeat- 
edly and in the most different order, so that they must be- 
come familiar with a great many. Consequently, the ex- 
amination at the close of the term, while it should be 
most searching on species actually determined, may also 
extend to other minerals in general, and finally embrace 
the rapid and certain determination of some species not 
before examined by the student.* 

223. A mineral is a native chemical 
compound (221). Each mineral species, there- 
fore, is homogeneous (96), and contains its constituent 
elements in fixed proportions (97), so that its composition 
can be represented by means of a chemical formula (184). 

224. We shall learn that each such compound has also 
quite definite physical and morphological properties (El. 
Phys., 214) ; so much so, that a careful observation of 
these physical and morphological properties (in most cases) 
leads with certainty to the chemical composition, while 
inversely, in theoretical chemistry, these properties are 
deduced from the chemical constitution. 

Accordingly, we give in the next section a concise 
synopsis of the physical and morphological properties of 
the principal minerals, so that the student can learn the 
composition of each mineral, as indicated by its chemical 
formula. The concise synopsis of properties of a mineral 
is called the characteristic of that mineral. 

225- Some minerals are actually almost chemically 
pure, and as free from any accidental ingredients as if 
they had been prepared with great care by an able chem- 
ist. But usually, more or less of matter not essential to 
the mineral has got into the same while growing in the 

* Localities are not given, because the naming of a few places is absurd and leads 
to gross errors. The teacher, in excursions, etc., may exhibit the actual occurrence 
of minerals, and reier to certain well characterized mineral regions in our land. 
More about this in "Cosmos." 



Elements of Mineralogy. 119 

midst of the diverse materials amongst which we find the 
mineral. Such matters are termed imp u r i t i e s. 
They are often readily recognized in minerals of vitreous 
luster, having changed the color of the same. Thus, rock 
salt, when chemically pure, is white, and has vitreous lus- 
ter ; but a very little of organic matter tinges it green, 
blue, red, yellowish, etc. 

But if the luster is metallic, a slight amount of impurity 
is not so readily detetected. This gives rise to the follow- 
ing highly important practical rule : 

The color of a mineral having metal- 
lic luster is constant, i. <?., characteris- 
tic; but the color of a mineral not hav- 
ing metallic luster is variable, i. e., not 
characteristic. 

Examples — Metallic: Pyrite, Galenite, Gold. Non- 
metallic: Quartz, Calcite, Fluorite. 

226. All minerals having essentially the same 
composition, differing only by what may be termed im- 
purities, belong to the same species of mineral. ' If 
their differences are sufficiently plain, they may individu- 
ally be distinguished as varieties. See description 
of quartz (61) next section. 

Such variation also extends, in a small degree, to spe- 
cific gravity and hardness. In a few cases, the crystal 
form, and consequently the cleavage varies also ; 
but although the last named modifications thus produced 
gives rise to varieties only, we shall, in the next sec- 
tion, follow the prevailing custom, and describe these mor- 
phological varieties as distinct species. Compare cal- 
cite 181.1 with Aragonite, 181.15; Pyroxene 203.3 with 
Amphibole 203.4; also, Eutile 61.4 with Brookite 61.5 
and Octahedrite, 61.6. Such minerals are properly merely 
morphological varieties of the species represented by the 
chemical formula. If there are two such varieties, the 
compound is said to be d i m o r p h o u s (181 and 203) ; if 



120 Chapter VII 



there are three, the compound is trimorphous, as 
Ti0 2 in 61. 

227. Several species, the chemical formula of which 
differs only in the electropositive element, 
constitute a genus of mineral species, especially if the 
electropositives belong to nearly allied genera of elements. 
Compare 111, and the formula at the head of the first gen- 
era in the next section. Each mineral will be represented 
by two figures, the first indicating the genus, the 
second, the species. If varieties exist, they are de- 
noted by a ^letter. Thus: 15, 2, c is cadmiferous 
sphalerite. See next section. 

According to the electronegative, we group genera into 
orders and classes, as explained 123, and exempli- 
fied in the next section. 

227. The members of a class of minerals may be 
distinguished by chemical means. Thus, the sulphides 
emit the odor of burning sulphur when heated on charcoal 
before the blow-pipe. Also, orders are chemically 
characterized. Thus nitrates deflagrate (95, note), silicates 
cause the soda-bead to effervesce (why, see 190), carbonates 
effervesce with acids (186). 

Upon the application of such facts depends the determ- 
ination of minerals by chemical means, an art which can 
only properly be acquired in a special course in de- 
terminative mineralogy. 

228- The entire system of minerals is repre- 
sented graphically on plate III. in a new manner, em- 
bracing the three most important properties, namely, 
hardness, H as ordinates ; specific gravity, G 
as abscissae ; and chemical composition, by the 
curve joining the species of the same genus. 

In reality, a species on this chart occupies a certain 
area, because both H and G vary slightly (see the char- 
acteristics in next section). The dot representing 
the species on our chart is determined by the mean 



Elements of Mineralogy. 121 



values of H and G as given by the upper figure to 
the right of the main figure in the characteristic; the varia- 
tion or range is given to the right, and below, at the 
6ame place. For hardness, the small figures indicate 
fourths; for gravity, they are tenths. Finally, H 
and G are always given in the second line, H preced- 
ing G. Thus, in genus 101, species 2 (see next section), 
we find H expressed by 3J and G by 3? ; that is, a mean 
hardness 3J with range J, so that H varies from 3 to 3-J ; 
also, G- 3.9 mean, range 0.1, or varying from 3.8 to 4.0. 
This species 101. 2 (Celestite), is therefore represented on 
the chart by a point, the abscissa of which is G =* 3.9, 
while its ordinate is H = 3f (Compare El. Phys., 74). 

On this chart, the sulphides (to the right) and the sili- 
cates (to the left) are represented by full down lines ; the 
carbonates by a waving line ; all other genera by dotted 
lines. Anhydrous species are represented by dots, hy- 
drated by minute circles, for the oxygen compounds. Chlo- 
rides and Fluorides by a dot with circle, Elements by a 
star. 

229. The student can readily determine the hardness 
and specific gravity of a given mineral with an accuracy 
of one-half of a unit (El. Phys., 150 and 123). He 
then finds the point on the chart represented by the 
mean value of II and G determined by him. The dot 
representing the mineral must then be found on the chart 
inside a square extending one-half unit (1 cm. on the 
chart) each way from the above point. The student en- 
ters in his Journal all species of the chart occurring 
inside this square (by the number of genus and species) ; 
by careful comparison with the description or characteris- 
tic of each of these minerals given in the next section, he 
finds which properties in the descriptions conflict 
with those observed ; all such conflicts he enters in his 
Journal. The species not conflicting is the one which he 
has in hand. In this manner our chart is not only a con- 
16 



122 Chapter VII 



cise representation of the system of minerals, but also a 
most important guide in the determination of minerals. 

230. The student having received a mineral for de- 
termination, carefully ascertains the optical, morphological, 
and molar properties of the same, and H* and Gf (com- 
pare El. Phys. 216), entering a concise statement of 
his results in his Journal (for abbreviations, see 231). I n 
this work he should use the material 
(mineral) furnished, precisely as directed. 
He should not try hardness of crystals, 
because that would injure the faces, 
nor try hardness on the larger, uncrys- 
tallized piece, given for the observation 
of luster, color, and cleavage faces. Nor 
should he break off fragments from 
either of the above to observe streak 
or cleavage, but he must use one of the small frag- 
ments expressly given for this purpose, which frag- 
ments must also be used for the determ- 
ination of hardness, unless an extra piece 
is given expressly for this purpose. 
Finally, the minute fragments resulting from experiments 
on cleavage and streak must be put into the vial for that 
purpose.:): The teacher must enforce these rules, for 

* The hardness should be determined according toMohs' scale (El. Phys., 
150). 1, Talc. 2, Gypsum. 3, Calcite. 4, Fluorite. 5, Apatite. 6, Feldspar. 7, Quartz. 
8, Topaz. 9, Corundum. 10, Diamond. 

A crystal fragment of 2, 3, 4, 6, 7, is quite sufficient to serve as scale for student's 
work . 

fit is advisable to use a balance weighing to the centigram; then 

w 

w— w' 
Where w = weight in air, w' = weight in water (El. Phys., 123). 

% The teacher will see, from the above, what material is required. For any one 
species the material is best kept in a small paper box, which is handed to the stu- 
dent for use, with card label giving any special directions deemed necessary in re- 
gard to the material. 

In each such tray is another card, containing the number of the mineral (genus 
and species; also, letter indicating variety) in accordance with the descrip- 
tion given in the next section. This card the teacher does not show to the stu- 
dent, but puts it aside ; he gives the student merely the current number in the 
teacher's private note-book, where he enters the name of student receiving the min- 
eral, also genus, species, variety of mineral given. The student's reported result 
is also entered, so as to determine the value of the student's work. This note- 
book thus reads, for example: 

315. Mr. Johnson . . 181, 1, g . 181, 1, g 

316. Miss Davies . . 203, 3, c . 203, 3, f 

317. Mr. Evans . . 230, 6 . 230, 6 



Elements of Mineralogy. 123 

otherwise no school can afford to give its pupils the mate- 
rial for this work free ; hence, infringements of these 
rules must be followed by a f i n e sufficient to replace 
the injured specimen. Since the teacher has a record of 
the students who have used the specimen, this rule can 
be enforced. 

In case but a single crystal is accessible, the teacher 
may state on a card those properties which to determ- 
ine would injure the specimen ; hence especially, H, 
cleavage and streak. Most specimens will, how" 
ever, without actual trial, exhibit both 
the directions and degree of cleavage; 
smoothness of plane faces in fracture indicate rather 
perfect cleavage, while pearly luster indicates a highly 
perfect cleavage. At other times, the cleavage is also 
sufficiently manifest from cracks in the specimen. 
The card accompanying the specimen will give directions 
in this respect. .For further details, see the example in 
232. 

231. Abbreviations. For H and G already ex- 
plained in 228. 

Angles are given in degrees and tenths thereof; 
thus, 0.1 is 6 minutes, and 121.6 — 121°36' inside of 3' 
either side. This is more than accurate enough for these 
Elements. 

Cleavage, Civ (El. Phys. v 197, 198). Degrees: 

em eminent (highly perfect). impft imperfect. 

pft perfect. diff difficult. 

dst distinct. tr traces. 

Luster, L (El. Phys., 208,209): 
vit vitreous prl pearly, 

ad adamantine* slk silky. 

m metallic. res resinous, 

sm sub-metallic. gr greasy, 

d dull, earthy. wx waxy. 

•Like a diamoud. 



124 



Chapter VII. 



Diaphaneity or Opacity (El. Phys., 205, 206): 
trsp transparent. strp semi-transparent. 

trl translucent. strl trl on edges. 

op opaque. 
We give luster first, and often omit diaphaneity, if suf- 
ficiently determined by the luster; see El. Phys., 209. 



Color 


, col., and Streak, str., the names of col- 


ors (El. Phys., 210): 






bl blue. bn brown. 




bk black 


gr green. gy gray. 




etc and other colors. 


dk dark. dp deep. 




: -ish. 


or orange. p purple. 




r red. 


w white. y yellow 




var various. 


clrl colorless pi pale. 




It light. 


For exarr 


tple, gr:y = greenish yell 


ow. Also, bn, etc. = 


brown, and other colors; im] 


plying. 


, however, that brown 


dominates. 






Form 


(El. Phys., 199; 


also, 


subsequent 233) and 


Structure: 






a 


amorphous. 


tr 


triclinic. 


pr 


prism. 


m 


monoclinic. 


py r 


pyramid. 


r 


rhombic. 


dm 


dome. 






b 


base. 


q 


quadratic. 





octahedron. 


h 


hexagonal. 


d 


dodecahedron. 


E 


rhombohedral. • 


h 


hexahedron. 


t 


tessera!. 


E 


rhombohedron. 








Structure and Aggregation : 


cpt 


compact. 


fol 


foliaceous 


cryst 


crystalline. 


gran granular. 


mass 


massive. 


fib 


fibrous. 


rad 


radiated. 






ren 


reniform. 






stal 


stalactite. 






stell 


stellate. 







Elements of Mineralogy. 125 



We are fully aware of the fact that this chapter is no 
interesting reading, but if the student carefully studies 
this chapter and works according to the directions here 
given, we know that he will be deeply interested. See 222. 

232. The following may serve as an example, car- 
ried out according to the directions in 280. The student 
should, however, constantly bear in mind all that has been 
said in this. section, in order to arrive at correct results: 

No. 372. Mineral. 
Description : Yitr. strl. w. H 6f (x 3.4 Form — no 
crystal given. Civ. 1 em ; 2, forming pr. 130, pft,in same 
zone. Angle em: pft 115°. 

230.4 Axinite — 3 3 civ. 1 dst. 

240.2 Prehnite — 2? civ. 1 dst. 

221.3 Fibrolite civ. 1 pft. 

221.1 Cyanite 5 to 7 3f civ. MT 106.3. 

205.2 Epidote — gr. civ. M pft, T less 10, MT 115.4. 

205.1 Zoisite — 3? civ. 1 pft, striat. longit. 
81.4 Diaspor — — — — 

207.2 Yesuvianite civ. 2 dst. 80°. 
207.1 Garnet 7 2 3 6 cryst. civ. dodec. 

Hence, the given mineral is Diaspor, 81.4. 

In a great majority of cases, the determination will be 
easier than the one here selected. 

233, A single crystal, if only one of its extremi- 
ties is sufficiently well developed, is quite sufficient to de- 
termine the mineral. As stated in 230, the hardness, 
cleavage, and streak should not be actually determined on 
the crystal, but be stated to the student by the teacher.* 
Cleavage and streak may, in most cases, be omitted en- 
tirely, if the form is carefully investigated according to the 
following directions (Compare, also, El. Phys., 174, 175) : 



* In actual practice, when a new specimen has been found, H, Civ. Str, are determ- 
ined careiully on those portions of the crystal which are either broken, or not de- 
veloped. 



126 Chapter VII 



See whether the crystal has a plane of symmetry, or 
not. If it has no plane of symmetry, it is triclinic; 
it is then one of the following minerals: 130, 5 ; 161 ?1 ; 
211, 2 ,3 ; 221 x ; 230, 4 ; 275 ?1 . Compare figures 48, 49, 50 
and the description of these species. 

If the crystal has a plane of symmetry, place this 
plane vertical fronting you; then the crystal has symme- 
try of right and left. JSTow ascertain whether it 
has symmetry of back — front or above — below. If it 
has no symmetry but right and left, the crystal is mono- 
clinic, and must be one of the following minerals : 22, 1 ; 
91, 1 ; lll, i; 180*; 141, 1 ; 171, 1 ; 181, 20 ; 200,^; 203, 2 , 3 , 4 ; 
205, 2 ,3 ; 211 t ; 230, 2 ; 240, 9 , 13 . Compare, also, Figs. 40 
to 47. 

If, however the crystal has an additional plane of sym- 
metry (above — below or front — back), then it is either 
rhombic, like Figs. 18 to 28, or it has rotary sym- 
metry besides. A crystal has rotary symmetry 
if its faces appear precisely the same (also, in inclinations) 
after a rotation of 60°, 90°, or 120° around the vertical 
axis of symmetry. If, after a rotation of 120°, the 
crystal in three positions appears the same, the crystal 
is rhomb ohedral (R), like figures 30 to 38 ; in these 
forms each face occurs exactyly three times about the 
vertical in the same relative position. If the angle be 
60°, then each face occurs six times, as in Fig. 29, and 
the crystal is hexagonal (h). If the angle of rotation 
is 90°, then each face occurs four times, and the crys- 
tal is quadratic (q), as in figures 13 to 17. 

But if a crystal finally have both the rotary symmetry 
of 90 degrees around one axis, and of 120 degrees around 
another, it is both q and R, or tesseral (t), as in figures 
1 to 12. Instead of this statement, we may also say that 
tesseral crystals have three axes of quadratic sym- 
metry. 

The following are the minerals having these degrees of 
symmetry : 



Elements of Mineralogy. \21 



Rare: 4, 1 , 2 , 3 ; 5 5l ; 15, 10 ; 45, lj2 ; 61 5l ; 64, lj2 ; 80 n ; 130, 6 ; 
151,2 ; 181,i, 2 , 3 , 4 « 7 , 8 ; 201 ?1 , 3 , 4 ; 214, 2 ; 230, 3 ; 240, 8 , 15 . 

bare: 12* ; 31, 10 ; 67, 2 ; 71, 10 ; 80, 2 ; 135, lj8 ; 220, 2 ; 
230 n ; 240, 17 . 

qare: 31*; 61, 3 , 4 , 6 , 7 ; 83*, 2 ; 88, 2 , 3 ; 90*; 207, 2 ; 220, 2 ; 
240, 5 . 

t are: 1,11253 ; 2*; 3*, 2 , 4 ; 11*; 15*, 2 ; 18, 2 , 3 ; 41*, 2 ; 
67 n ; 71,i 5 8i ?2?3; 82,! ; 84*; 130* ; 165*, 2 ; 207*; 
220*, 4 ; 240* ; 271* ; 281*, 2 . 

r are: 5, 2 ; ll, 2 *i,2i> 13*5 21*, 2 , 3 ; 45, 3 ; 61, 15 \ 81*, 4 ; 
83, 3 ; 84, 2 ; 88* ; 101* ;2 , 3 , 4 ; 130 n , 2 , 3 ; 150,!, 3 , 4 ; 151*; 
181*5*6*7*8^ 201,2 ; 203,! ; 205 x ; 214*, 3 , 4 ; 221, 2 , 3 ; 230, 5 , 6 ; 

240, 1 , 2 , 3 , 4 , 6 ,7,i2,i 4 *6>20 j ^ 0, 2 . 

After the degree of symmetry has been determined, the 
specific gravity and hardness alone will suffice to reduce 
the number of possible mineral species which the 
crystal may be from the above given lists to very few. A 
closer inspection will then decide which of these few the 
crystal is. 

To decide on the degree of symmetry, often more careful 
measurements are required than the student can make. 
Thus, chalcopyrite (see 31^ was considered tesseral, even 
by Hauy, until Haidinger's careful measure- 
ments proved it to have but one axis of quadratic sym- 
metry (Fig. 16.) In such doubtful cases, the student must 
of course pass all species above given under the possible 
degrees of symmetry. 

234. The student should, in this connection, carefully 
review El. Phys., 190, 191, 194, 195, and 199. He will 
then remember that the truncature of the corners of the 
octahedron (Fig. 1) give the hexahedron — cube — (Fig. 3) ; 
also, that the truncature of the edges of the octahedron 
gives the dodecahedron (Fig. 2). He will then also readily 
see that the truncature of the edges of the hexahedron 
(Fig. 3) likewise leads to the dodecahedron, while the 
truncature of the corners of the hexahedron leads back to 



128 Chapter VII 



the octahedron. Finally, the trflncature of the four-sided 
corners of quadrative symmetry in the dodecahe- 
dron gives the hexahedron, while truncature of the three- 
sided corners of rhombobedral symmetry leads from 
the dodecahedron to the octahedron. Compare the fig- 
ures 1, 2, and 3. The angles between these faces remain, 
also, constantly the same ; namely (see El. Phys., 190) : 
hh' 9G. Q oo' 109. 5 dd' 120. o 

ho 125. 3 hd 135. od 144. 7 

These three forms, therefore, occur together (see Fig. 8), 
in combinations. Other tesseral forms, resulting 
in a similar way from either of these three, are : 

The Ieuci'toid, or trapezohedron, Fig. 5 ; the g a- 
lenoid, Fig, 4; the fluoroid, Fig. 6; the a d a- 
m a n t o i d, Fig. 7. 

These forms are complete, and are termed holohe- 
dral; but if only the alternate faces in the octahedron 
(Fig. 1) are retained until they intersect, the tetrahe- 
dron (Fig. 11*) results. If corresponding part of Fig. 5 
is developed, the c up r o i d (Fig. 12) results, while from 
Fig. 6 follows, in a slightly different manner, the p y r i t o- 
h e d r o n, shown in Fig. 10, in combination with the 
hexahedron. See minerals : 165 n ; 41 n , 3 ; ll n . 

Further particulars about crystal form must be sought 
in special works on Crystallography (See the author's 
Principles of Pure Crystallography). Enough will here 
have become evident to create the conviction in the mind 
of each student, that the forms of crystals are determined 
by mathematical and physical laws of the deepest interest 
and the highest importance to physical science. 

•This shows the faces of the other tetrahedron, also. 



SECTION II. 



DESCRIPTIVE MINERALOGY. 

Class I.— Native Elements. 

Most are metals, possessing both metallic luster and 
malleability. 

1. Cdpkoids, Ko. Important minerals. 

1. Gol d. An. m. y. 
2 1 3 17 30 tClv. 0. mall. gran. 

2. Silver. Ag. m. w. 
2 3 10 8 tClv. 0. mall. 

3. Copper. On. m. r. 
2^cClv. 0. mall. 

2. Sideroids, Id. Only in meteorites. 

1. Iron. Fe. m. gy:w. 

4 2 73tClv. 0. magnetic. Meteoric iron; usually 
containing considerable Ni, also, a little Co. 

3. Titanoids, TV. Nearly infusible. 

1 . P 1 a t i n n in. Pt. in. gy:w. 
iJlT&tClv. 0. gran. 

2. Palladium. Pd. m. gv:w. 
4fll|tClv. 0. gran. 

11. G r a p h i t e. C. sm-d. bk. 

lp^Clv.lpft. 
10. Di a m o n d. C. trsp-op. colrl. etc. 

10 3 5 tClv.4:,octah.pft. Hardest body ; most cost- 
ly gem, diamond of n carat, worth $60.ir. 
Above n=20, much more. Black dia- 
m ond is cheaper ; opaque. 
17 



130 Section II 



4, Phosphoids, 0. Bp. incr. 

1. B i s in u t li. Bi. m. r:w. 
2l9 7 R,87 7 Clv.P.pft; 6 forming 2 rhomboh. of 

69.5 less so. Fig. 38 ; important ore. 

2. Antimony. 8b. m. gy.w. 
316 7 R,87.6.Clv.P.em. 3 forming 1 rhomboh. 

117.1 cist. Fig. 38. 

3. Arsenic. As. in. gy:w. tarnish. 
3 2 5 9 E,85.7. Clv.P. impft (Fig. 38). 

5. SULPHOIDS, 0. 

1. T e 1 1 u r i u m. Te. in. w (Fig. 38). 
2j6fR,87.0Olv.3,apr.l20,pft.P,irapft. 

2. S u 1 p h u r. S. res. y. 
2 2 2 1 r,pr.Ml01.8Glv=2pr.impft (Fig. 27). Ob- 
tained in great quantities. Po.l08.3-Pp.ll7.7. 

Class II. Sulphides — Single and Double. 

Bp. odor of burning S (231). G high, above 3, and H 
low, usually below 4, except for pyrites (H= 6). Metallic 
luster; opaque and brittle, with few exceptions. 

Double sulphides contain usually As or Sb, indicated 
Bp. by garlic odor or white fumes. 

A. Single Sulphides. 

11. Pyrites, 2djR 2 . 

1. Pyrite. FeS 2 *. m. pale, brass, y.Str.gribk, 

br:bk. 

6}5^tClv. 0. Forms, h, o, d, and pyritohedron, 
f, Fig. 10 ; h striated parallel to edges. 
Beautiful forms, — the gem among sulphides. 
h'f'153.4,f f'"126.9 ; a, common ;'b, contains 
gold in most gold regions (Auriferous P.), 
but not in other localities. Exceeding abund- 
ant. Syn : fool's gold, iron pyrites. 

♦Dimorphous, two distinct forms; distinguish by form, color, G. 



Descriptive Mineralogy, 131 

2. Marcasite, Fe S 2 *. m. bronze-y ; gr: 
Str.gyibk. 
6}4?r,pr.M106,l clv.2 pr.M prft (Fig. 23). Often 
rad. 1LS0 3 . 
11. Arsenopyrite, FeSAs. m. w. Str. gy:bk. 

5f61r.pr.Mlll.9clv.2 pr.M dst. Mispickel.11,99.9. 
21. L e 11 c o p y i' i t e, FeAs 2 . ra. w. Str. gy:bk. 
5i'7|r, like 11. white pyrites. This genus con- 
tains also species containing Ni.,Co. 
12. Subpyrites, 2oR. 

1. jSTiccolite, Ni As. m. copper-r. Str. br. bk. 
5}7|h. tarnish bk. Principal nickel ore; vulg. 
copper nickel. 
15. Galenites, KdS. 

1. G-aleni t e.f Pb. m. Col. Str. lead-gy. 
2 2 72tclv.3, cube, em. (Fig 8.) a, Principal lead 

ore ; b, often contains a little silver, which 
is obtained by cupellation ^see 168). Argen- 
tiferous galena. 

2. Sphalerite, Zn. res-ad. trsp-trsl. br,bk, 

etc. Str.w.etc. 
3f44tclv.6, dodec. em. Var. a, pure, w. cleio- 
phane ; b, br, bk, contains iron, marmatite 
or blackjack, c, contains Cd, is radiated, ad. 
luster, Przibramite. 
10. Cinnabar, Ilg. ad-dull. r. Str. scarlet. 
2J9°R, 92.6 civ. 2, a pr. 120, pft. Mercury ore. 
18. Chaloooites, Ku 2 S. Important ores. 

1. Chalcocite, Cu. m.col. Str.bk:gy. taruish.gr. 
2?5 2 7 r, pr.M119.6 clv. 2 ,M impft (Fig. 21). Cop- 
per-glance, vitreous copper. 

2. B o r n i t e, Cu. m. r— br. Str.gy:bk. 

3 4cl t civ. 4, octah.tr. Contains much Fe. 
Horse-flesh ore, from colors of tarnish. 

f Hereafter, only the electro-positive in the species is given, the one represented 
by the general symbol in the genus. 



132 Section II 



3. A r g e n t i t e, Ag. m. bk:gy. Str.m. 

2}7ft civ. 6, dodec. tr. Silver-glance, vitreous 
silver. 

21. Stibnites, <P 2 S s . 

1. Bismuthinite, Bi. ra. gy. tarnish. 

2 6 4 r, pr.91.5 clv.2pft, 1 impft, at right-angles 
to each other. 

2. S'ti b n i te, Sb. m. gy. 

2 4 5 r, pi-. 90. 9 civ. lcm. Antimony glance; 
principal Sb ore. 

3. O r p i m e n t, As. prl, res. strsp.-strsl. y. 
l?3 3 r, pr.100.7 clv.lem. Compare 22, 1. 

22. 1. R e a 1 g a r, As S, res. Col, r, Str, or. 

lJ3?ni. clv.2pft. 

30. 1. Molybdenit e, MoS 2 . m. <;y. Str.gr:gy. 

im % clv.lem. 

B. Double Sulphides, or Sulphosalts. 

31. 1. Chalco p y ri t e. Fe 2 S 4 0n 8 . m. deep brass-y. 

str.gnbk. 

3?%, nearly t. civ. indsl. Fig. 16. oo'109.9. 
oo'" 108.7; in tesseral (Figs. 11 and 1). 
oo'=oo"==109.5. Copper pyrites, good cop- 
per ore. 
31. 1<>. P y r r h o t i t e, FeS? m. bronze y-r. str.gy:bk. 

4 2 4 6 h Fig. 29. clv.P.pff. 3 pr. M of 120 less so. 
Magnetic ; hence name : magnetic pj'rites. 
35. 1. B-e r t h i e r i t e, FeS 4 Sb 2 . in. gy-bn. 

2P1 ? civ. 1 indst 
41. Teteahedbites, RJUfl^ Fahlerze. 

1. Tetrahedrite, Cu-Sb. m. gy-bk to r. 

3|4ft, tetrahedral, Fig. 12. Half of trapezohe- 
dron, Fig. 5, with half of octahedron, Fig. 1. 

2. T e n n a n t i t e, Cu-As, m. bk: str. r:gy. 
3?45t. civ. 6. dodecah. impft. These often con- 
tain Ag in place of Cu. 



Descriptive Mineralogy . 



66 



45. PrKARGYRiTES, RS 3 <P. Rothgueltigerze. 

1. P y r a r g y r i t e, Ag-Sb. m-ad. bk-r. Str. r 
2J5*R10S.7 the civ. 3, R irapft. Ruby sil- 
ver ore. Dark reel silver ore. Figs. 31, 32. 

2. Proustite, Ag-As. ad. strsl. Col. Str. cochi- 
neal-r. 

2j5fE, 107.8. Light-red silver ore. 

3. B o u r n onit e, Pb and Cu, S. m. gy-bk. 
2|5fr, pr. 93.7, civ. 3, impft. at 90°. 

Class III. Oxides — Single and Double. 

Most vitreous luster ; in general, II greater and Ox less, 
than for sulphides. ]\ : o single and simple chemical test 
distinguishes these, the most numerous of all minerals.* 

The double oxides, or salts, are also easily distinguished 
by order reactions ; for example, the carbonates (227). 

Hydrated minerals are also easily distinguished from 
anhydrous, by the former yielding water when heated in 
a glass tube (92). 

A. Single Oxides. 

61. QUARTZITES, 7V0 2 . 

1. Q u a r'tz, Si. v-res, d. colrl, etc. Str. w. etc. 
7, 2| R, 94.25. civ. none. 

Fig. 30. RR=rr==9L25. Rr 133.7 KM 
=Mr==141.8 M striated horizontally. R and 
r often nearly equal in size, so that the crys- 
tals appear hexagonal. Varieties : 

A. Crystallized, a, Rock Crystal, trsp. colrl ; 
b, Amethyst, trsp. violet; c, Rose Quartz, rose 
col.; d, Smoky Quartz, y:br, often trsp; e, 
common cryst. quartz, trsl. col. various. 

B. Massive crystalline, f, common quartz 
rock, g, milk} 7 quartz, h, ferruginous quartz (red). 

* Test is not necessary either, for if not S-ides, nor elements, it follows that a 

given mineral belongs to the oxides. The fourth class contains but few. 



134 Section II 



0. !N"ot crystalline; res luster, strl-trsp ; i, 
chalcedony, gy, bn, etc.; k, carnelian, r. ; 1, 
chrysoprase, apple-gr; in, prase, dull leek-gr; 
n, plasma, bright gr; o, heliotrope, plasma 
with small spots of red jasper. 

p. Agate, various (i to o) usually banded 
so as to form a variegated stone, q, if bands 
even planes, especially great contrast in colors 
(bk— w, bn-w), onyx. 

r, Flint, only strl, gy, bl: Splits off in sharp 
edges ; tough. 

s, Hornstone; more brittle, less trsl than flint. 

JD. Opaque, dull; t, jasper, colors various, 
often variegated (Ribbon J) ; colors mostly r 
and y from iron, u, Basanite (Lydian stone, 
touchstone), black, flinty jasper. ; v, silicious 
sinter, deposited from silic. water ; w, Quartz- 
sandstone, grains of quartz ; x, sand, loose, 
irregular grains of quartz. 

2. Opal; hydrated Si0 2 . vit, res, prl. trsp. op. 
col. various, play. 

6 2 2| amorphous. Varieties : 

a, Precious opal, brilliant, delicate play of 
colors ; b, fire opal, red tints predominate in 
colors ; c, common opal, w, y, bl, r. ; d, semi- 
opal ; e, wood opal, y: w:, structure of wood ; 
f, hydrophane, trsp in water; g, hyalite, colrl. 
trsp. globular crusts; h, silicious sinter; i, 
jasp-opal ; k, tripolite. 

3. C a s s i t e r i t e, Sn. ad. trsp-op. bn-bk. str. 
gy: bn: 

616] q. civ. pr. \ Fig. 13 (isom 61,7) Mo 133.6 
Mh 135. Tar. a, ordinary, tin-stone — mass ; 

b, wood tin, masses of concentric layers, rad. ; 

c, stream tin, gran, loose like sand and gravel. 
The only tin ore. 



Descriptive Mineralogy. 135 



4. R u tile, Ti0 3 in-acl. strl-op. r:bn. Str. bn, pale. 
6}4 2 q, Fig. 13, isom. 61. T civ. 2 (M) (list, 2 (h) 

less sol o(/ 123.1, Mo 132.3, Mh=135. 

5. Brookite, Ti0 2 . m-ad. str. bn. Str. gy:, y:. 
5?4?r, civ. 1. 

0. Octahedrite, Ti0 2 . m-ad. trl. br:, bl. str. 

clrl. 

413?q, Fig. 14, civ. 5, pit. (P and o) oo'97.9, 
tP 119.4, oP 111.7. Anatase. Hence, TiO 2 
is trimorphous ; distinguish by form, cleav- 
age, G. 
7. Zircon, Si and Zr. ad. trsp-op. clrl y: br, 

etc. str. clrl. 

7 3 4| q. Fig. 13. civ. 2 (M) impft. 4 (o) less dst. 
oo' 123.3 Mo 132.2. Yery rich in forms, 
gems clrl y, jargons ; br, or, r: hyacinths. 
15. P y r o 1 u s i t e,* Mn. m. op. bk,gy. str. bk. 

2}4 8 r, pr.93.7. cl. 4, in 2 zones. Principal 
source of Mn ; black oxide of Mn. Impure : 
Wad. See 83, 10. 

64. Hematites, 2V a 8 . 

1. Corundum, Al vit, prl. trsp-trl, Str. clrl. 
Col. var. 

9 4? K, 86.1 (Fig. 38), civ. P, pftf; also R. 
Trsp. crystals, gems ; a, sapphire bl. ; b, ori- 
ental ruby r, ; c, oriental amethyst o, ; d, oriental 
topaz, y ; e, oriental emerald, gr. 

f, not trsp. ; massive or cryst, corundum, gy, 
bl:, bn: etc. 

g, Massive, op. bk, gy:bk, containing magnet- 
ite and hematite — emery. 



* Given by way of appendix to this genus, to which it does not properly belong, 
f But not continuous. 



136 Section II 



2. II e m a t i t e, Fe. m. d. bk,gy. Str. eherry-r. 
6 2 4J. R,86.1. civ. 1. P and 3, K,indst. nn 143.1, 
ss 122.5. Beautiful crystals : Elba Hoses, Fig. 
34. Yar : a, specular iron, ra;if fol. micaceous; 
b, compact col. or fibr. — red hematite ; c, red 
ochrous H. — earthy, clayey (reddle) ; d, clay 
iron-stone, impure, hard; at times, oolitic. Im- 
portant iron ores. 
67. Periclasites, KuQ. 

1. Periclasite, Mg. vit. trsp-trsl. gy-gr. 
6 3 T t civ. 3, cube, pft. 

2. Z i n c i t e, Zn. ad. deep r. Str. or. 

4} h\ h civ. 1, b. em. — . Red zinc ore ; 
important ore. 
71. Cuprites, Ku.fi. 

1. C u p r i t e, Cu. ad-sm. r. str. bn:r. 

3f 6 2 t civ. 4, octah. Ordinary: a, red copper 
ore, cryst. or mass ; b, tile or e, impure: 
from iron oxide. 
10. Ice, H. vit. trsp. clrl. str. w. 
2 0.92 h, Fig. 39, a snow star. 

80. Hydrated Oxides. 

1. Brucite, Mg0 2 H 2 . prl, slk. tfil. w:ete. str, gy. 
2 2 2f-E 82.4 Fig. 38. Civ. P, em. basal; var. 

a, common, fol. ; b, nemalite, fibr. 

2. G i b b s i t e, A1 2 6 H 3 . prl. vit. w: 

3° 2f h, small hexag. cryst. ; civ. 1, em. 

B. MetalloSxVlts. 

81. Aluminites, R0 4 A1 2 . 

1. C h r yso b eryl, Be. vit, trsp-trl. Col. var. 
Str. clrl. 
8 2 3^ r, Civ. 3 dst (M M T), nearly hexag. pr. 

and perpendicular to P, base, impft. Fig. 20. 

MM 119.8, MT 120.1. var. a, ordinary, pale 



Descriptive Mineralogy. 137 

gr. b, Alexandrite, emerald gr in reflected 
light, deep red by transmitted light ; crys- 
tals most beautiful, often large, in groups, 
resembling snow-stars. 

2. Spinel, Mg. vit. trsp-op. Str. w. Col. var. 
8 3| t Civ. 4 (oct). a, red, ruby, b, dark gr, 

br, bk, etc. Pleonast. Finer, varieties, gems. 

3. G a h n i t e, Zn. vit. grs. strsl-op. dk gr. Str. gy. 
7f 4| t, like 81.2. a, Automolite, pure Zn. b, 

Dysluite, contains Zn and Mn. c, Kreitton- 
nite, Zn and Fe. 

4. D i a s p o r, H 2 . vit, prl. trl strl. w:, gyi^ gr. 

6J 8} r Fig. 20. Civ. T em, pr. MM' less so; 
TMM' six-sided pr, MM' 129.8, TM 115.1. 

82. Chkomites, R0 4 Cr 2 . 

1. Chromite, Fe. sm. op. bk. str. bn. 

5 2 4i t, mass, gran. Chromic iron ; the prin- 
cipal source of Cr. Impurities : Mg - Al. 

83. Manganites, K0 4 Mn 2 . 

1. Hausmannite, Mn. sm. op. bn:bk. Str. bn. 
5} 4 7 q. Civ. 1, basal, pft. See 82, 1. 

2. B r a u n i t e, Mn. with Si. sm. bn:bk, str. bn:bk. 
6} 4J q, very nearly t. 

3. Manganite, H 2 . sm. op-strl. gy-bk. str. 
r:bn, bk. 

4 4| r, pr. 99.7 Civ. 2, the pr. pft ; 1, cutting 
off the acute angle of pr, more so. 
10. Psilomelane, 5| 4| sm. bk,- amorphous. 
Impure, W a d. H i to 6. G 3 to 4.3. See 82, 1. 

84. Magnetites, K0 4 Fe 2 . 

1. Magnetite, Fe. m-sm. op. bk. str. bk. 
6° 2 &l t ; o and d. Civ. 4, o. Always strongly 
magnetic ; often magnetized (El. Phys., 303, 
304, 323) 3 when called lodestone. Magnetic 
iron ore ; abundant, good. See 82, 1. 
18 



138 Section II. 



2. G o e t h i t e, IT 2 . ad. strl. y:, r:, bk:bn. str. bn:y. 

5J 41 r, pr. 94.9. Olv. 1, very pft. 
10. L i in o n i t e, H n . slk, sm, d. bn. str, y:bn. 
5| Z\ a. Iron ore, varieties : a, cmpct, sm, 
brown iron stone, b, Ochreous, more y, 
also earthy, clayey, c, Bog ore, porous, 
d, Brown clay ironstone, cmpct, often gran, 
grains small ; e. Oolitic ; large ; f, Pisolitic, 
Brown hematite, ochre, etc. 
88. Wolframites, KO^Wo. Wolframates. 

1. Wolframite, Fe, Mn. sm. op. gy:, bn:bk. 
Str. r:bn, bk. 
5J 7 2 3 r pr. 101.1. Civ. 2, at 90°. 

8. Scheelite, Ca. vit-ad. trsp-trl- w: str. w. 
4f 6; q. pyr. 100.1 Civ. 4, pyr. dist. Tungsten. 

9. S t o 1 z i t e, Pb. res-s:ad. strl. gr, gj, etc. 
Str. clrl. 

3° 8J q. pyr. 99.7. Civ. 1 impft ; 4 more so. 

90. 1. W u 1 f e n i t e, Pb0 4 Mo. res-ad. strl-strsp. y, 

etc. Str. w. 

3 6| q, pyr. 99.7. Civ. 4, pyr. pft. Lead 
Molybdate. 

91. 1. C r o c o i t e, Pb0 4 Cr. ad-vit. trl. r. Str. or. 

21 6? m. pr. 93.7. Civ. 2 pr. dist. 

C. Salts (proper ). 
a, Sulphates, anhydrous; 111, 130, hydrous. 
101. Barites, R0 4 S. 

1. Anhydrite, Ca. prl. vitr. w, etc. Str. w* 
3} 2jj r, pr. 100.5. Civ. 3, pft. at 90°. 

2. C e 1 e s t i t e, Sr. vit-prl. trsp-strl. bl:, w. Str.w. 
3J 3? r Fig. 24, pr. M 104.0 Civ. P pft, pr. M 

dist. Usually columnar after Pq. 

3. Ba r i t e, Ba. vit-res. trsp-op. w, etc. Str. w. 
3 2 4| r, pr. M, 101.7 Civ. P, pft; M, less so- 
Heavy spar, Fig. 24. Usually tabular after P. 
Pq 127.3. Pr 141.1 



Descriptive Mineralogy. 139 



4. Anglesite, Pb. ad, res, vit. trsp-op. w, etc. 

Str. w. 

3 6? r, pr. M, 103,7 Civ. 1, Pand 2, pr. Lead 
vitriol. Fig. 24 ; often rather equally extend- 
ed in the three dimensions. 
111. G yps li in, Ca0 4 S+2H 2 0. prl-d. trsp-op. w, etc. str.w. 

1? 2 3 m, Fig. 43, if 111.4 11 143.7 Civ. 1, P, em, 
fol. ; 1, M, con choidal ; 1, T fibr, 
silky ; both at right angles to P, and MT 
113.1. Var. : a, Selenite, when cryst, trsp. 

b, Satin spar, fibr. slk ; plumose g., rad. fibr. 

c, Massive g: alabaster, gran, w; rock-g, 
less pure. 

130. Various Hydrated Sulphates. 

1. Kieserite, Mg S-ate, 13°/ water, w. 
2 2 2 5 r — slightly soluble. 

2. E p s o m i t e, Mg S-ate, 51% water, w. 

2 1 l 7 r, nearly q. Civ. 1 pft. efnor. Epsom 
salt, El. Phys., 185. Sol. 

3. G o s 1 a r i t e, Zn S-ate, 44°/ water, w, 

2} 2? r, nearly q. Civ. 1 pft, efnor. White 
vitriol, El. Phys., 184. Sol. 

4. M e 1 a n t e r i t e, Fe S-ate, 45°/ water, pale gr. 
2 I 8 m, nearly K. Civ. 3 ; P pft, M less so. 

Fig. 40. MM' 82.3 ; PM 80.6. Sol. Green 
vitriol. Efflor ; turns y, ochery. 

5. Chalcanthite, Cu S-ate, 36°/ water, bl. 

2 2 2 2 tr. Civ. 0. Fig. 50. Sol. MT 123.1 
PT 127.7 MP 109.9 Tn 148.8 Pn 120.8. 
Blue vitriol, copper vitriol. El. Phys., 177. 

6. A 1 u n i t e, Ka-Al S-ate, 13% water, w. 

3? 21 E, 89.1. Civ. P, pft. Fig. 38. Alumstone. 
10. A 1 u m s, various. See El. Phys. 194, 195. 
t. sol. 

b, Phosphates, anhydrous ; 141, 150, hydrous. 



140 Section II 



135. Apatites, K Cl 2 + 3(R. 3 [0 4 P] 2 ). Fig. 29. 

1. Apatite, Ca. vit-res. trsp-op. gr, etc. str. w. 
5 31 h. Fig. 29. Civ. P, impft. pr. M more so. 

Asparagus stone. Osteolite, phosphorite. 

2. Pyromorphite, Pb. res. strsp-strl. gr, br, 
etc. Str. w, y: 

2>l 6° 3 h Civ. tr. Fig. 29. a, Green lead ore. 
b, Brown lead ore. 
141. 1. Y i v i an i t e, Fe P-ate, 29% water, w, bl: str. 
clrl, etc. 
1? 2} m, pr 111.2 Civ. 1, pft ; 2, tr. 

150. Various Hydrated Phosphates. 

1 . S t r u v i t e, Mg-H P-ate, 44% water, vit. 
trsl-op. y: 

2 l 7 r, Civ. 1 pft. The same as microcosmic 
salt. 

3. 1 i v e n i t e, Cu P-ate, 3% water, much As. 
ad-vit. strl-op. gr:bn. Str. gr-bn. 

3 4| r pr. 92.5 Civ. tr. Olive copper ore. 

4. Wavellite, Al P-ate, 28% water, vit-prl. 
trsl. w, gr, y, bn. bk. Str. w. 

31 2 3 r pr 126.4 Civ. 2, pr. pft; 1. Usually 
rounded concrete, rad. fibr. structure. 
6. T u r q u o i s, Al P-ate, 20% water ; with Cu. 
wax. strl-op. bl, bl:gr, gr. Str, w, gr: 
6 2 7 a. renif.stalact. Calaite, Oriental T; 
finer var. as gems. 

c. Titrates. 

151. Nitratites, KaOsN. Deflagrate on Chic. 

1. N i t r e, Ka. vit. strsp. w. Str. w. 

2 l 9 r (Fig. 26). Civ. M, impft. MM' 119.4, 
Mo. 120.3, DJJ' 109.8. Saltpeter (see El. 
Phys., 181) ; sol. 

2. Nitratite, Na. vit. strsp. w. Str. w. 

1? 2\ K, 106.5 (Fig. 31). Civ. 3, E, pft. Chili 
saltpeter (El. Phys., 186) ; sol. 



Descriptive Mineralogy. 141 

cl. Borates. 

161. 1. Sassolite, hydrogen borate, prl. w. 

1 l 5 tr. Civ. 1, em. sol. 
165. Boracites, ROJBo, part of O replaced by Cl. 

1. Boracite, Mg. vit-ad. trl. w,y:,gr: 

7 (massive 4. 2 ), 3f t, tetrah. Civ. 4, oct. tr. 
The massive variety yields water. 

2. Khodizite, Ca. vit-ad. trl. w. 

8 3? t, isom. 165.1. 

171. l.Borax. Na 2 O 7 Bo 4 +10 PI 2 0. vit-res. w. 

2J l 7 M (Fig. 44). Civ. K, pft ; T less so. TT 
87. , oo' 122.6. 

e. Carbonates. 
Effervesce with acids. 181 anhydrous. 200 hydrated. 
181. Calcites, R0 3 C. Dimorphous, esp. Ca. Species 1 
to 8, isom. 151.2 ; species 15 to 18, isom. 151.1. 
1. C a 1 c i t e, Ca. vit-d. trsp-op. w,etc. Str. w,gy: 
3 2 2} R, 105.1. Civ. 3 (R) em. Forms, very 
rich — dominant are : 

1. Fundamental rhombohedron, R, fig. 31. 

2. Hexag. pr. M of 120.0, with rhombh. r 
of 135.0, fig. 32. 

3. Scalenohedron S, fig. 33, with R (Dog- 
tooth spar) ; angles SS' 144.4, SS" 104.6, 
SS"' 133.0. 

Varieties exceedingly numerous : 

a. Crystallized ; finest, trsp. Iceland spar ; 
all clear cryst. : Double spar, showing 
double refract (El. Phys. 291). 

b. Fibrous: Satin spar, silky. See 111.1. 

c. Granular, cmpct: 

d. Crystalline, Marble proper, e, w. 
saccharoidal limestone. f. Variegated, 
cryst. or cmpct: Marbles, numerous 
varieties. 



142 Section II 



g. Compact limestone, gy, w, etc. 

b. Lithographic stone, very fine grained. 

i. Hydraulic limestone; impure, either 

cloy or Mg. 
k. Shell marble, coralline marble, etc., 

from fossils. 
1. Chalk, soft, friable, w. m. Eock-meal, 

rock-milk, exceedingly friable, w. n. 

Marl, very clayey. 
o. Oolite, gran, concretions; p, if large, 

pisolite. 
q. Stalactites (hanging), and, r, stalagmites 

(standing) cones, etc., in caves ; often 

fine structure, caucentric layers, various 

colors. 
s. Tufa, calcareous sinter, deposits from 

calcareous waters. 

2. Dolomite, Ca, Mg. vit-prl. strsp-trl. w, etc. 
Str. w. 

3 3 2 s R, 106.3, isom. 181.1. Civ. 3 (R), pft. 
Pearl spar, cryst. curved faced, prl. Brown 
spar, w, y:, turns bn after exposure to air, 
from Fe-ous C-ate. Gran., cmpct, rock. 

3. Magnesite, Mg. vitr. trsp-op. w, y:, bn. 
4 2 3 2 R, 107.5. Civ. 3 (R), pft. isom. 181.1. 

If ferriferous, Breunerite. 
4:. Smithsonite, Zn. vit-prl. trsp-trl. w, 
^j: gr: bn. Str. w. 

5 4} R, 10T.T. Civ. 3 (R), pft. isom. 181.1. 
Calamine, formerly. Drybone of miners. 

7. Rhodochrosite, Mn. vit-prl. trl. rose, etc. 
Str. w. 

4 2 3? R, 106.9. Civ. 3 (R), pft. isom. 181.1. 
Rose spar. Diallogite. 

8. S i d e r i t e, Fe. vit, prl. gy, bn, etc. Str. w. 
4 2 3? R, 107.0. Civ. 3 (R), pft. isom. 181.1. 



Descriptive Mineralogy. 143 

Crystal-faces often curved. Yar. : a, crys- 
tallized ; b, granular; c, massive caucretion. 
ary (spherosiderite) ; d, oolitic. Spathic iron 
ore. Chalybite. 
Many intermediate varieties; especially: Mes- 
i t i t e, Mg and Fe ; A n k e r i t e, Ca, Eg, Fe. 

15. A r agon it e, Ca. vit-res. w, gj^ gr. etc. 
Str. w. 

3? 2 9 r, pr. M 116.2. Civ. 1 (b), diet, 2 (M), 
and 2 (D), indist. Mb 121.9, Db 125.8, DD' 
108.4 (Fig. 26). 

16. Strontianite, Sr. vit-res. w, gy, gr, 
etc. Str. w. 

3} St r, pr. M, 117.3. Civ. M pft, b trs (Fig. 
26). DD' 108.2. Isom. 181.15. 

17. "Witherite, Ba. vit-res. w, y:, etc. Str. w. 
3? 4 3 r, pr. M, 118.5. Civ. 2 (M), dist. Mb 

120.7. Isom. 181.15. 

18. C e r u s s i t e, Pb. ad-vit, res. w: etc. Str. w. 
3} 6 5 r, pr. M, 117.2. Civ. 2 (M), impft. Isom. 
181.15. 

Many intermediate varieties. Crystals of 15-18 
quite frequently compound internally, like 
snow-star, because MM' nearly 120; visible 
externally at times, otherwise internally, by 
polarizing microscope (El. Phys. 296). 
20. B a r y t o c a 1 c i t e, Ca, Ba. vit-res. w, etc: 
Str. w. 

4 3 7 m, nearly R of 106.9. Civ: 3 (R). 
200. Htdrated Carbonates. 

1. Az u r i t e, Cu. 5°/ water, ad. bl. Str. bl. 
4 3 3| m, Civ. 2 pft. 1 dst. 2 tr. 

2. M a 1 a c li i t e, Cu, 8°/ water, ad-slk, d. gr. Str.gr. 
3f3? m, indst. fibr. Important ore for Cu. 

3'. Tron a, Na, 22 water, vit. gy. Str. w. 
2?2* m. Civ. 1. sol. 



144 Section II 



F. Silicates. 

201. Phenacites, R 2 4 Si. 

1. Phenacite, Be 2 . vit. clrl. etc. Fig. 32. 
7 3 3R, 116.3 Olv. 3 (M) dst ; 3 (R) indst. En 1 60.0 

2. Chrysolite, AIg 2 . vit. gr. (olive) etc. Str. clrl. 
6|3Jr. Fig. 18. Civ. 1 (T) dst; M indst, hh 119.2 

Olivin, olivenite; in grains. Also found 
crystallized in meteorites. 

3. Will e mi te, Zn 2 vit-res. y: etc. Str. clrl. 
5 2 4°R, 116.0 Civ. 3 (M) dst; 1 (basal) in others. 

Isom. 201.1. 

4. D i o p t a s e, Cu.H 2 . vit. emerald gr. Str. gr. 
5 3 3 R 126.4. Civ. 3 (R) pft. rr 95.5. 

203. Enstatites, R0 3 Si. 

l.Enstatite, Mg. vit-prl. gy: etc. Str. gy 
Fig. 44. 203.3. 
5 2 3? r, pr. 87.0. Civ. 2, T, easy, M, K less so. 

2. Wollastonite, Ca. vit-prl. w. etc. Str. w. 
4?2? m. Civ. 1 dst ; 1 (110.2 to first) less so. 

Tabular spar. 

3. Pyroxene, Mg-Ca-Fe ; at times, Al. Pres- 
ence of Fe indicated by color and G. With- 
out Few; a little Fe, gr:, shade of gr. deepen- 
ing, till with much Fe, bk. G increases with 
amount of Fe — . 

5131 m, Fig. 44. Civ. 2, T, pft. nearly 90°. 2, 
M and K, less so. TT' 87.1 ; MT 136.4 ; TK 
133.6 ; oo' 120.5 ; PK 106.0. Varieties : a, b, 
G<3.4. c, G>3.4. 

a, Malacolite, Ca-Mg ; w, y, to pale gr. 

b, S a h 1 i t e, Ca-Mg-Fe ; gy:gr. to gr, bk. 
The bright grass gr, trsp. Diallage. 

c, Hedenbergite, Ca-Fe, bk. 

e, F a s s a i t e, gr, often trsp. ) 

+• a • 4. 1 1 v, a r Contain Al. 

i, A u g i t e, bk, bn, deep gr. j 



. Descriptive Mineralogy. 145 

4. Amphibole, Mg-Ca-Fe ; at times, Al. 
See preceding species, which only differs in 
form, cleavage, and G. Compare genus 
181. Fig. 41. 

5|3| m, Civ. 2, T pft, nearly 120°. 1, M, 
imperfect. TT' 124.5 ; TM 117.7 ; PT 103. o; 
oo' 148.0 ; Po 145.4, so that o Po' nearly a 
rhombohedron. Varieties : 

a, Tremolite, Mg-Ca; w.2.9<G<3.1. If 
tough, fine grained, Nephrite, H>6 ; 
also, called Jade. 

b, Actinolite, Mg-Ca-Fe ; bright gr, gj: 
gr, G 3.0-3.2 ; usually stellate, fibr. Less 
than 6% Fe. 

c, Asbestus, fibrous var. of above ; col. var. 
mostly w or w: Chrysotile, mountain leath- 
er, m. cork, m. wood, different varieties of 
asbestus. Amianthus, if silky. 

d, Pargasite, grblrgr, lustrous. ) 
^Hornblende, gr:bk, bk. } Contain AL 

205. Epidotes, E0 3 Si+fR , 2 3 H-iSi.0 2 . 

1. Z o i s i t e, Ca, Al. prl. gy:w, etc. Str. clrl. 
6J3? r, pr. 116.7. Civ. 1 pft. Crystals usually 

long, striated lengthwise. 

2. E p i d o t e, Ca, Fe, and Al. vit-res. gr, y:gr, 
br:gr. Str. gy. 

613} m, Fig. 42. Civ. 1, M, pft; 1, T, less so, 
MT 115.4. Tb 128.3, DD 109.5, Mb 116.3. 
Slightly diff. from 151.1 (Nitre). Pistacite. 

3. Piedmontite, Ca, Mn ; Fe, Al ; vit-prl. 
r:bn, r:bk. Str. r: 

6 2 5 4 m, isom. 205.2, same civ. 
207. Granatites, R'A+3 [R0 3 Si]. 

1. G a r n e t, Al, Fe, Cr ; Ca, Mg, Fe, Mn. vit- 
res. trsp-trl. Col. various. Str. w. 
7 2 3J t, Civ. 6, dodec. dst: Fig. 9, common com- 
19 



146 Section II. 



bination of d (Fig. 2), and t (Fig. 5), which 

also occur singly. Chemical name composed 

of name of prevalent It' and R, in general 

F^-R-garnet. 
a, Grossularite, Al-Ca- ; 3.4<G<3.7. Colors: 

w; palegr; y: ; bin; cinnamon stone. 
1), P y roj) e, Al-Mg- Fiery red ; Bohem. 

garnet. Much used as gem; usually found 

in gravel. 
e, A 1 m a n d i t e, Al-Fe- ; oriental garnet, 

precious g. — deep r. trsp. Common g. — 

bn:r, trl. 

d, S p e s s a r t i t e, Al-Mn-. G, from 3.7 to 
4.4, r. p:r. 

e, A n d r adit e, Fe-Oa. G, from 3,6 to 4.0. 
Several sub varieties, fine y:, bn: to bk, 
called resp. Topazolite. Colophonite, Mela- 
nite. Allochroite contains also, Mn. 

f, Onvaro v i t e, Cr-Ca- Emerald gr. Ac- 
curate determination of the variety requires 
often a careful quantitative analysis ; the 
above represents only the principal types ot 
the varieties sctually occurring. 

2. V e s n v i a n i t e, Al-Ca, mainly, vit-res. gr 
to bn. Str. w. 

6 2 3 4 q (Fig. 17). Civ. 2, M, dst ? 1, P, less so. 
Form very nearly t ; Pe 142° 46'. Several 
varieties. Id o erase. 
211. Feldspars, Be 4 Al 2 -f2Si0 2 (Fig. 47). 

One cleavage, P, pft to em ; a second, M, less 

pft, and nearly at right angles to P. Other 

cleavages impft. or faint, vit-prl, trsp-trl. w. 

etc. Str. w. 

1. Orthoclase, R=Ka 2 , e=0-fSi0 2 (Ka- 

Feldspar). 



Descriptive Mineralogy. 147 

6}2? m. PM 90.0 (Fig. 47). Tl 118.8, PT— Pl= 
112.2, Tx 110.7. 

a, Adularia, glassy, w. trsp. 

b, Pegmatolite, vit-res. col. var (n). 

c, Amazon esto ne, bright gr. 

d, compact orthoclase. 

2. A 1 li i t e, K=Na 2 , £=0-hSi0 2 (Na Feldspar) 
61 2 (i tr, PM 86.4 (Fig. 48). Tl 122.2; PT 

114.7; PI 110.8; TM 117.9. 

3. A northite, K=Ca, s=0 (Ca- Feldspar). 
6 2 2 2J tr. PM 85.8 (Fig. 48). Tl 120.5 ; PT 

114.1 ; PI 110.7. 

4. Other feldspars are composed of the above, 
grown together in line laminae, and in various 
proportions (Tschermak). This is especially 
evident in Perthite. The different feldspars 
grow together along M, so that on P they are 
best distinguished, because PM differs for the 
different feldspars. Examples : 

a, Perthite, Ka (red) and Na (vv) Feldspar. 

b, Oligoclase, Albite predominates over, 
Ka and Ca. <* 

c, A n d e s i t e, Albite and Anorthite in nearly 
equal proportion ; but little Orthoclase. 

d, Labrador! t e, Anorthite with Albite. 
Labrador exhibits peculiar play of colors, gr. 
bl, y dominating. 

e, Snn-sto n e, A vent u r ine, a Feldspar 
containing minute crystals (of 64.2 ?) which 
produce lire-like reflections of light. 

f, Moonstone, a feldspar showing whitish 
opalescence. 

g, Obsidian, bk, glassy (volcanic). 

h, P i t c h s t o n e, waxy, amorphous masses, 
of composition like feldspars, g and h des- 
titute of cleavage. 



148 Section II 



214. Micarites. Anhydrous silicates ; Ka-Al, etc ; Civ. 
1 (basal) em ! yielding elastic fol. prl- 
trsp-trl. Str, w. Often in short hexagonal 
columns, like Fig. 29. 

1. Muscovite, or Potassium-mica. 

2{ 2| r, pr. 120.0. Civ. 1, em ! light colors (Two 
optical axes, El. Phys., 295). 

2. B i o t i t e, or Magnesium-mica. 

2? 21 JR," Civ. 1, em! dark colors, bk, etc. 
(One optical axis, El. Phys. 294.) 

3. P h 1 o g o p i t e, or Magnesium-mica with Ka. 
2? 2 8 r Civ. 1 em ! y:, bn:, etc (two optical 

axes, near together). 

4. L e p i d o 1 i t e, or Lithion-mica. 
$1 2? r, Civ. 1, em. rose, p, lilac. 

220. Unclassified Species. 

1. L e u c i t e. vit. trl-op. gy. Str. clrl. 

5? 2 5 t Civ. 6, dodec. very impft. Crystals, 
Fig. 5 ; which is therefore called leucito- 
hedron. 

2. E"ephelite. vit-grs. trsp-op. w, y:, gr:, etc. 
Str. w. 

5? 2? h, Fig. 29. Civ. 3, M, disk; 1, P, impft. 
a, Sommite, glassy, small cryst. b, Elseolite, 
greasy, large, coarse cryst. 

3. Werner it e. vit-prl; trsp-strl. w. or light, 
etc. Str. w. 

51 2; q (Fig. IT). Civ. 2, d, dst ; 2, M, less so. 
Scapolite ; many varieties. 

4. Lapis Lazuli, vit. trsl-op. Rich bl. Str. bl. 
5} 2 4 t, dodec (Fig. 2). Civ. 6, dodec. impft. 

221. Cyanites. Al 2 5 Si ; Polymorphous, as below : 

1. Cyanite. vit-prl. trsp-trl. bl: etc. Str. clrl. 

5 to 7. 3f tr (Fig. 49). Civ. M pft; T, less so. 

P, impft. TM 106.3 ; PM 100.8 ; PT 93.3 ; 

Mo 90.3; M dominates; prism, after TM 



Descriptive Mineralogy. 149 

Striated MP on M. H=4 to 5 on M in di- 
rection of edge TM, but 6 at right angles 
thereto. H = 7 on T and P, especially to- 
wards edge PT. Some crystals may be sub- 
stituted for a compass needle (Pliicker) Dis- 
t h e n e, because of varying H. 

2. Andalusite, vit-d. trsp-op. w: etc, r: Str. 
clrl. 

7\ %\ r (Fig. 28). Civ. M, impft; 2, tr. MM 
90.8 ; hence, nearly q. 

a, Ordinary A-, b, Chiastolite, or made, 
H 3 to 7, according to degree of purity. 
Blackish impurities from rock (shale) distrib- 
uted regularly in cross sections of crystal, in 
form of a cross, or otherwise. See figure. 

3. Fibrolite, similar to above (1 and 2) but 
form r. pr. 96 to 98, only 1 civ. very prft. 

230. Silicate-Gems (except 5). 

1. Beryl. Al 2 [0 3 Si-j-BeQ 3 Si] 2 vit-res, trsp-strl. 
Str. w. 

7 3 2 7 h (Fig. 29). Civ. P, impft. ' 

a, Emerald, bright emerald gr. from Cr. 

b, B e r y 1, pale gr, bl:, y:, w. 

2. E u c 1 a s e, hydrated Al-Be-Si-ate. vit-prl. 
trsp. Clrl. pale gr. bl: Str. clrl. 

V 3 1 m (Fig. 46). Civ. T, em. 2, q, impft. ss 
115.0 ; ff 105.8 ; qq (in zone with f) 49.1. 

3. Turin aline. Boro -silicate ; charact. by 
form. vitr. trsp-op. Col. var. Str. clrl. 

7 1 3j R (Figs. 35 ? 36, 37). Civ. tr, R; brittle, 
esp. crosswise. RR 103.0 ; oo 133.1 ; 11 60.0 ; 
si 150.0; ss 120.0. As in figure, crystals 
often hemihedral : only 4 of equal faces 
present, also, h e m i m o r p h o u s, the two 
extremities differing, as in figure. 



150 Section II. 



While changing its temperature, turmaline 
has electrical polarity ; one extremity -f E, 
the other — £. Figure indicates the E dur- 
ing & o o 1 i n g. This property is termed 
P y r o 1 e c t r i c i t y. In direction of axis 
usually opaque, even if across axis, trap. 
Hence, use as Polarizer (El. Phys., 296), 
plates being cut out para] lei to axis. Varieties: 
a, Aehroite, clrl. b, Rubellit e, r, 
rose, ruby, c, P e r i d o t o f C e y 1 o n, hon- 
ej-y. d, Chrysolite, Brazilian emerald, 
or peridot, gr. e, Brazilian S a p h i r e, 
Berlin bl ; I n d i c o 1 i t e, bl, bbbk. f, A p h- 
r i z i t e, bk. g, Columnar and black, 
most common, brittle crosswise. 

4. A x i n i t e, Boro-silieate 

vitr. trsp-strl. bn: etc. Str. clrl. 
6? 3 s tr. Civ. I dst. ; others indst. 

5. S t a u r o 1 i t e. Al-Fe Si-ate. 
vit-res. trl-op. bn, bn:bk. Str. clrl. 

7} SI r (Fig. 22). Civ. o dst, M traces. Crystals 
grow together under 90° or 60° to form 
crosses. Staurotide. 

6. T o p a z. Al 2 (0,Fl 2 )Si ; Al Si-ate, with Fl. 
vit. trsp-strl. y: etc. Str. clrl. 

8 3f r (Fig. 19). Civ. P, pft. MM 124.3 ; 11 
86.9; Ml 161.3; PM=P1=90.0; Py 117.7; 
Pf 136.4 ; Px 1 V-«. p u 134.4 ; Pi 145.8 ; 
strongly electri e<< -j-E) by friction. 

a, Ordinary in cr\ - -, which, however, nearly 
always are >••• i •■.<■ , showing only one ex. 
tremity. 

b, P y c n te : •" i ict, columnar. 

240. Htdrated Silicates; JNos. 3 to 9, are Zeolites; 13 
to 16, Makgarites. 
1. Calamine, Zn. vit-ad. trsp-trl. w: Str. w. 



Descriptive Mineralogy. 151 



4f 31 r (Fig. 25). Civ. M, pft ; o, pft $ P tr. 
MM 103.8; oo 117.2; pp 57.3 ; Mb 128.1 ; 
Fp 118.7; mm 69.8; Pm 124.9; ss 101.6. 
Hemimorphous; compare 230.3 ; also pyro- 
electrical. 

a, Crystals; implanted on rocks with the py- 
ramid s. 

b, Impure, with carbonate and clay; calamine. 

2. P r e h n i t e, Ca, Al, vit. strp-trl. gr: w: Str. w. 
6} 2? r, Civ. 1 dst. 

3. Th o m s o n i t e, Ca, Al. vit-prl. trp-trl. w, 
bn: Str. w. 

5J 2? r (Fig. — ). Civ. M easy ; b less ; P tr. 
MM 90.7 ; Mb 134.4. 

4. N a t r o 1 i t e, Na, Al. vit, prl. trp-trl. w, etc. 
Str. w. 

5} 2 2 r, acicular, librous, stellate. Fibrous 
Zeolite. Mesotype. 
4*. A n a 1 c i t e, Al. Na. vit, trsp-op. w: Str. w. 
5} 2 2 t (Figs. 5, 8). Civ. 3, cube, traces. Analzine, 

5. A p o p h y 1 1 i t e, Ca, Ka. prl-vit. trsp. w, etc. 
Str. w. 

4? 2 4 q. (Fig. 15), Civ. P em; M pft. MM= 
MP=90.0. Po, 119.5. Ichthyophthalmite, 
iisheye-stone. 

6. Harmotome, Ba, Al. vit. w, etc. Str. w. 

4 2 2 4 r, pr. M, 124.8. Civ. 2 (M) and 1, base P. 
Baryte-Harmotome. 

7. P h i 1 1 i p s i t e, Ca, Al. vit. w, etc. Str. w. 
4} 2 2 r, pr: M, 91.2. Civ. 2, at 90°. Lime- 

Harmotome. 

8. Chabazite, Al, Ca. vit. trp-trl. w, etc. 
Str. w. 

4 3 2 1 K. Civ. R, dst. RR94.8. G melinite, 
or Na-Chabazite, similar; angles different. 

9. Stilbite, AJ, Ca. vit. trsp-trl. w, etc. Str. w. 



152 Section II 



3? 2} m (Fig. 45). Civ. M pft, N impft. PIST 
129.7, JSTT 116.3, PJVI 90.0. Heulandite, a 
variety. 

10. Serpentine, Mg. res-grs. trl-op. gr: etc 
Str. w. 

2 to 4. 2 6 a. massive, slaty. Massive. 

a, precious S, rich oil gr, trh H 2-J-3. 

b, Common S, darker, strl, H up to 4. 

c, Retinaliteis resinous, d, P o r c e 1 1 o- 
p h i t e has a fracture like porcelain. 

e, Lamellar S, rather rare. 

f, foliated S, M a r m o 1 i t e, fol. brittle. 

g, fibrous S, Chrysotile. 
h, columnar, Picrolite. 

i, Serpentine Pocks, of which the 
finer varieties are k, Serpentine Mar- 
ble, often beautifully veined. 

11. S e p i o 1 i t e, Mg. gy: w, y:, r: w. - op. 

2} - 0.9, floats on water ! Smooth feel, earthy 
or clayey texture. Meerschaum. 

12. Talc, Mg. prl-grs. strsp-strl. gr: etc. Str: w. 
1} 2J r. Civ. 1, em ! fol. gran. Feel, greasy. 

a. Foliated Talc, b.' Steatite, Soap- 
stone, massive, gy:, gr:. Coarser kind: c. 
Potstone, finer grained, d. French Chalk, 
e. Indurated Talc is harder, impure, f. 
Talcose Slate, argillaceous rock, contain- 
ing talc enough to impart the greasy feel. 

13. C h 1 o r i t o i d, Al, Fe. prl. trsp-trl. gy, gr. 
5? 3 5 m. Civ. 1, em. fol. brittle. 

14. Margarite, Al, Ca. prl. trl-strl. gy:, y:. 
Str. w. 

4§ 3 r. Civ. 1, em. fol. brittle. Pearlmica. 

15. P e n n i n i t e, Al, Fe, Mg. prl-vit. trsp-strl. 
Col. var. Str. w. 

2J 2\ E, 65.6 (Fig. 38). Civ. P, em. Laminae 
flex., not elastic. 



Descriptive Mineralogy. 153 

16. K i pi d ol i t e, Al, Mg, Fe. prl. trsp-trl. deep, 
gr, Str. gr: w. 

2J 2J m. Civ. 1, em. Laminae flexible, some- 
what elastic. Chlorite, Clinochlore. 

17. P r o c h 1 o r i t e, Al, Fe, Mg. prl. trsp-trl. 
gr. Str. gr:. 

If 2? h. Civ. 1, em. Lam. flex., not el. Chlor- 
ite. — Crystals often implanted on edge. 

Dichroism. — The green minerals 15, 16, 
17 often appear red, if seen in the direction 
of cleavage. Compare 81.1. 
20. K a o 1 i n i t e, Al 2 (0 3 Si) 3 ; H 4 replacing one 

Si. prl. d. trsp-trl. gy: y: bn: etc. Str. w. 

1 to 2-J-. 2f r, minute plates, nearly hexag. 
Kaolin. Porcelain Clay. — Bole, r. 

Clays are impure hydrous Aluminium silicate. 
Fire-clay, Pipe-clay, Clay, Loam. 

Class IV. Fluorides. 

271 1. F 1 u o r i t e, Ca Fl 2 . vit. trsp-trl. Col. var. Str. w. 

4 3} t (Figs. 3, 6, 5, 1). Civ. 4, octah. pft. 

Numerous forms and beautiful colors; hence, 

Erzblume (ore flower) of older miners, 

esp. as it accompanies many valuable ores. 

gr, bl, purple ; due to organic coloring matter. 

275. 1. C r y o 1 i t e, Na 3 Fl 6 Al. (Na Fluo-Aluminate) 

vitr, strsp-trl. w. ; at times bn, etc. Str. w. 

2 2 3 tr. Civ. 3 ; 1 pft, the other 2 less pft ; 

mutually nearly at 90°. 

281- 1. H al i t e, Na 01. vitr, trsp-trl. w, y: r: bl: Str. w. 

2 2 2 2 t. Civ. 3, cube, pft ; sol. Rock Salt. 
281- 2. Cerargyrite, Ag CI. res-ad. trsp-trl. gy: 
etc. Str. shining. 

1} 5} t [h, o, d]. Civ. none. Sectile. Horn 
Silver. Corneous Silver. Important Silver 
Ore. 
20 



154 Section II 



290, 1. C a r n a 1 1 i t e, Ka Cl 3 Mg+6 H 2 0. 

2 2 1.6 gran., mass, milk w; r: ; sol. 
290. 2. A t a c a m i t e, Cu, 01, Hydrate, ad-vit. trl- 

strl. gr, bright. Str. apple-gr. 

3{ 4} r, pr. 112.3. Civ. 1 pft, 2 impft. 

Appendix. Combustibles. 

A number of mixtures (96) of different serials (119) occur 
in large quantities ; several of these mixtures are very 
largely used as fuel by modern industiy. Hence, although 
most of these substances rather belong to the rocks than 
to the minerals, it is advisable to give a short characteristic 
of the principal members at this place. 

All but anthracite burn with flame, the flame being due 
to the combustion of the volatile bitumen. Pure bitumen 
consists of C and H, and is fusible and inflammable. 

I. Mineral Goal. Blackish, solid ; dull to sub-metallic. 
Brittle. Infusible — some softening upon heating. 
Insoluble in benzine. H ■£• to 2£. G 1 to 1.8. 

1. Anthracite. H=2},- G=l| sm, glistening, 
often iridescent. Black. Only to three per cent 
bitumen ; no or feeble, pale flame. 

2. B i t u m i n o u s Coal. H=2, G==lf. Black, 
resinous luster, compact, firm, more brittle than 1. 
Varieties : 

a. Caking Coal; becomes viscid when heated 
in open fire or covered crucible ; residue left 
in latter case is Coke. 

b. Non-Caking Coal; heated in crucible 
yields no coke, but fragments retain their form. 

c. Cannei Coal (either to a or b) ; no luster, 
dull, black, smooth surface of fracture ; yields 
much burning oil when heated while air is ex- 
cluded (dry distillation). Torbanite is a 
brownish cannei coal. 



Descriptive Mineralogy. 155 



3. Brown Goal, usually less hard than the pre- 
ceding, G=li. Brownish to bn:bk, non-caking, 
often quite bituminous. L i g n i t e is a brown 
coal retaining the structure of 'wood*. Jet is a 
black, compact brown coal, susceptible of high 
polish. Earthy brown coal, rather friable. 
All brown coal yields an acid distillate, while 
black coal (No. 2) yields a distillate of alkaline 
reaction. Brown coal powder, boiled with potas- 
sium hydrate, colors the solution brown. 
Amber is a fossil resin ; r:, bn:, w:, to pure y. 

Str. w. trsp-trl. H=2l— G=1.06 to 1.08. Strongly 
— E on friction. Fuses 290°. Amorphous. Insoluble 
in alcohol and ethereal oils. Burns with yellow 
flame. Yields, upon heating in a closed tube, a 
whitish sublimate of succinic acid; the res- 
idue is soluble in ethereal oils. 
II. Bitumen. Black, lustrous, fusible solids, or liquids. 
Soluble in benzine. Highly inflammable. 

4. Asplialtum (m ineral p i t c h). G=1.0 to 
1.8. Pitch luster ; black; readily fusible at about 
100°. Ozocerite, G 0.85 to 0.90, fuses at 
about 60° ; trl. ; greasy to the touch. 

5. Pitt asp halt (m ineral t a r). Yiscid mass ; 
G<1. 

6. P e t r o 1 e u m, more or less limpid. G<1. 
Yields different coal oils by fractional dis- 
tillation, as Kerosene, G=0.8. G a s o - 
o 1 e n e, G=0.7. Compare note to 119. 

All these native materials, being not species (see 223), 
but merely mixtures (96), pass gradually into one another. 
They are also occurring in various rocks, such as limestones, 
and especially shales. Such shales yield bitumen upon 
distillation, and are used for the manufacture of coal oils. 

♦Mineral charcoal, black, soiling the fingers, rather fibrous, woody tex- 
ture. Small quantities occur i n the mass of other mineral coaU. 



CHAPTER VIII. 



THE CHEMICAL SCHOOL LABORATORY. 

235. ^ ne motto placed at the head of this volume 
occurs in the description of the grand Laboratory of the Uni- 
versity of Leipzig, published in 1868 by the director of that 
Laboratory, Prof. H. K o 1 b e. The motto asserts that chem- 
istry cannot be learned from books, nor even by attending 
chemical lectures (with experiments performed by the profes- 
sor before the class), but only by diligently working in the 
Laboratory. 

Hence the importance of a Chemical Laboratory for every 
school where chemistry is to be taught. 

236. But the students cannot be sent into the Labor- 
atory at the very beginning ; at least a class of students 
cannot. They must first become familiar with a multitude 
of facts and things by sight, before it is possible to trust 
them to handle the apparatus. We have adopted the 
following order in our instruction, which 
combines lecture, recitation, and labora- 
tory work, closing with a thorough exam- 
i nation. 

237. J- The class is assigned a lesson of twenty-five or 
twenty pages, preparatory to attending the lecture on the 
same. At this lecture the apparatus described in the lesson 
is exhibited, some of the experiments are performed (espe- 
cially all such as are not intended for students' practice). 
By casual questions, the teacher ascertains whether the 
students have studied the lesson sufficiently to follow him 
with advantage. Finally, in this lecture the teacher obtains 
an opportunity to produce that impression on the student 
which no printed page can produce ; thereby the real ad 
vantages of the lecture-system are secured. 

In these lectures the teacher may also add such general 



Chemical School Laboratory. 157 



views and special considerations as his own reading and prac- 
tice may suggest. Above all, the teacher should make the 
most of his apparatus and collections in these lectures, which 
thus will not only be highly instructive, but also attractive 
and deeply interesting. 

238. U-* These lectures are immediately succeeded by 
regular recitations, wherein each point is carefully ex- 
amined. On the average, two recitations are required to pass 
properly over the ground covered by one lecture. In these 
recitations the students are properly expected to know each 
apparatus described — for they have in the meanwhile again 
studied the description in the book, after having seen the 
apparatus in the hand of the teacher during the lecture. In 
these review-recitations especial attention must be given to 
all directions for work in the Laboratory, so that the students 
may know h o w to handle the appartus before entering the 
Laboratory, In these recitations the students' answers 
should, of course, be carefully marked on the class list- 
Thus the advantages of the so-called recitation system 
are secured in our mode of instruction in chemistry. 

239a UL In two, or at most three, weeks, the class 
will thus have been instructed in a sufficient portion of the 
book to be able to commence Laboratory Practice. 
That is, after having secured the advantages of both the 
more common systems of instruction by lectures and recita- 
tions — each student commences in the labor- 
atory a close and careful personal and ex. 
perimental study of the phenomena and 
facts of chemistry, which thus far he had only wit- 
nessed "from afar off," or merely read and talked about. 
Thus the double course of instruction preceding this labora- 
tory practice is to us only preparatory, fitting the stu- 
dent to profitably work in the laboratory — while in too many 
schools but one of the preceding modes of instruction is all 
that is given. 

240. I* Wl ^ invariably be found that students, in many 
particulars, fail to do as directed, and as they themselves 
have learnt during lecture and recitation. Hence con- 
stant supervision during laboratory practice is absolutely nee- 



158 Chapter VIII. 



essary, to refer the students to the proper directions in the 
book, and to see that even- thing is done in a proper way. in 
accordance with the laboratory rules. Mo one, who has not 
actually tried it, will believe how very great the difference is 
between word and deed; between '-talking about " 
a thing from book-study, and d o i n g the work in a labora- 
tory. 

2I4!L ^ ie student should enter a careful — concise 
and clear and neat — record of his experiments in the 
"Journal of Experiments " bound with this volume. In try- 
ing to do this, the teacher will find a great obstacle in the 
exceeding carelessness prevailing in most schools in regard 
to the writing of both words and figures. 

All work done in the laboratory must be immediately 
recorded by the student in his Journal of Experiments, and, 
before leaving the laboratory, this record must be exhibited 
to the superintending teacher, who enters the current 
n u in ber of his pocket record-book, while at the same time 
he enters the article worked and the name of the student op- 
posite that number in his own pocket-record*. This is nec- 

* We write all numbers like fractions, the tens as numerator, the units as 
denominator; thus No. 1572 is written 157.2 in the student's Journ il. A page of 
such record looks like the following, copied from Mr. Nipher's pocket record- 
hook: — 

/ Tocn/eu, J2o, a. 

Jo Isdcwmanj 7 07j a. 



£ <yfltU CSannei, //A, e. 









Chemical School Laboratory. 159 



essary, because the student's Journal of Experiments — not 
only in regard to quantity, but also in regard to quality of 
the work done and the neatness of the record itself — enters 
largely in the final class standing of the student at the close 
of the term. 

If the laboratory work is carried on in this manner, then 
the students become personally familiar with the 
facts, they learn to deal with realities, and thus 
really study chemis L r y, instead of merely a book*. 

242 IV« At the close of the term, the student passes 
an examination, at least on the general contents of tho 
book and the full details of those portions which he has prac- 
ticed. Compare El. Phys., 487, note. 

243, r l ne minimum of t i m e to be devoted to these 
different portions of the subject is, in hours per week : Lec- 
ture, one; review-recitations, two ; laboratory practice, two. 
The latter ought to be consecutive hours. Since no prepara- 
tion is required for these hours of practice, outside of that 
afforded for the lectures and recitations, each two hours 
practice is equivalent (in time) to o n e hour recitation ; 
for the latter does at least require one hour of previous 
study at home on the part of the student. Accordingly- 
on the basis of equivalence to five hours recitation (requir, 
ing five hours preparation) per week, the study of chemistry 
should be divided thus per week : 

Lecture — one hour, requiring one hour preparation. 

Kecitations — two hours, requiring two hours preparation. 

Practice, twice — two hours, requiring no extra prepara- 
tion. 

Total at school, seven hours; at home, three hours; in all, 
ten hours per week. 

244. P° r tne demonstration of any given article of this 
book, the student is furnished with the necessary set of ap- 
paratus, designated by the n u m ber of that article. Dif- 
ferent sets for the same article are distinguisned by letters 



* Chemistry and Physics, as usually taught hy mere lectures or recitations, 
re not Physical Science, but only additional literary studies. 



160 Chapter VIII. 



added. The pieces of apparatus or material are designated 
by the numbers 1,2,3, etc., following the number of the arti- 
cle. A card-label accompanies each set of apparatus, and 
contains a complete enumeration of all pieces. These labels 
are also copied in the general inventory of the laboratory. 
Each piece of apparatus has (if possible) a small label, com- 
posed of number of article (with letter) and number of the 
piece. Compare EL Phys., 496. 

The following may serve as an example of such a card- 
label : 



($4:^' iZiadua/ igjfoea&'n* 



/. ty/add /(am. 
J2. csbavvet 
O. <yncit, wiae a/at* 
^. tjAeifnotneJei, tyro. /. 
^f. <J ana -darn, tvim tana. 
$ca. 



$. £%)eaftei tvim fled/i wafel fno/ wet vc€\ 



ieive a 



dnou/a fladd micuaA cne o/ Jne Acted of \3> j 
<to/itug me meimonierfei f^r-J padded mioaan me omel. 

64* 

The label on the alcohol lamp will thus be — =— ; 

64 b 

on the beaker, — ^— . 



245i Ijarge apparatus, — like balance, barometer, etc., 
— do not, of course, accompany each set, but are put up in 
convenient places of the laboratory for general use. The 
wash-stand and general heating apparatus be- 
long also to the apparatus, of which but one need be provided 
for the entire laboratory. 



Chemical School Laboratory. 161 



A wash-stand is absolutely necessary. A simple, cov- 
ered round tank, placed a meter above a wash-stand, with 
faucet, wash-bowl, and drain will answer. The drain may 
even be omitted. A large, earthen jar, for the reception of 
filter, burnt matches, etc., may find a proper place under this 
wash-stand. 

A common American Cooking Stove (for wood) 
will answer excellently as a general heating apparatus. The 
oven will serve as air-bath. On the last two holes a pan for 
irons may be placed, containing sand ; this forms a capacious 
sand-bath (IS). On the two holes directly above the flame, 
a boiler, with faucet, may be placed, so that water (for wash- 
ing and experimental purposes) is always at hand. The 
boiler may be provided with holes and rings, so as to be 
used as water -bath (19) ; also, with tubes and condenser 
(59), so that distilled water may be made in the room. 

The Kerosene Stove, patented by E. B. M i t c h e 1 1,* 
will be exceedingly useful in all school laboratories not pro- 
vided with gas. His stove No. 1 is easiest managed; No. 
3 is most effective, but also most expensive. None of the 
more expensive furnaces are at all required for schools teach- 
ing these elements of chemistry. 

246i l De 8ets °f apparatus should be properly distribut- 
ed on the work-table, for the students' use. The students 
pass from one apparatus to another, and the apparatus is re- 
moved when all the students, or a sufficient number of the 
same, have performed the experiments therewith. A new 
apparatus takes the place of the one removed. 

24*7i ^ tne wor k-table — which may be the same as 
used for the elements of physics! — is provided with shelves, 
and especially with doors, the apparatus not in use may be 
preserved on the shelves or in these cupboards. Otherwise, 
some cases, or a separate room with cases, ought to be pro- 
vided for that purpose. 



* Winchester Avenue, 45, Chicago. 

f 80 cm. high, and 60 cm. wide i,El. Phys., 491.) 

21 



162 Chapter VIII. 



248. A separate laboratory is not absolutely necessa- 
ry for small schools ; for the work-table may run along one 
or more of the walls of the room, especially along the wall 
containing the windows. If a room adjacent to the school 
room is at disposition, it should be used as store-room, and 
as the teacher's laboratory, where apparatus and specimens 
can be prepared and preserved. Even larger schools do not 
absolutely require a laboratory, separate from the lecture or 
recitation room ; for if the room is properly ventilated,* the 
air will not be vitiated by the experiments required in this 
book. 

249s Much of the practice may also be performed at 
the common school-desk; especially all practice in Chapter 
YII. ; also, 205, 206, etc., etc. By a judicious distribution of 
the work, a comparatively large number of students may 
practice at the stands along the work-table, and at the com- 
mon school desks. 

250. -^ or further information on these topics, we refer 
to the first pages of the "Journal of Experiments," and es- 
pecially to the quarterly journal, — "The School Lab- 
oratory of Physical Science," — edited by the 
author. This journal, while of great practical importance to 
the teacher, is also of considerable use to the student, because 
it regularly brings series of laboratory work done by 
students. 



* If n o t properly ventilated, the room is not fit for recitation room either. Our 
school hoards, school directors, and even Christian presidents of colleges, are, 
however, very generally guilty of poisoning the children by vitiated air, due to the 
absence of proper ventilation in the rooms under their control. 



«# «««• 



JOURNAL OF EXPERIMENTS 



HINR1CHS 



ELEMENTS OF CHEMISTRY 



MINERALOGY, 



PERFORMED IN THE 



SCHOOL LABORATORY, 



UNDER THE DIRECTION OF 



AT 



LABORATORY RULES. 



1. Be Quiet. — Talk not to your fellow students, and only in low 
whispers to your teacher. Walk to and from the balance so that your 
steps are not heard. Early learn thus to show reverence for truth and 
its investigation ; the laboratory should be a temple of science. 

2. Be Certain. — Do everything <?o that no doubt can arise. Meas- 
ure, weigh, and record as directed, then you will be sure. Do not 
trust to your memory. D<- not assert anything of which you are not 
sure. Never guess — at most, estimate. 

3. Be Caueful. — Handle every apparatus precisely as directed, 
and as if it would require a fortune to replace it. See that everything 
is in good order when you receive it, and take pride in returning the 
same in excellent order to your teacher. 

4. Breakage of apparatus and waste of materials must immediately 
be reported and paid for, the student countersigning in the Laboratory 
Journal the amount paid. 

5. Throw nothing on the floor; put refuse matters in the stone 
jars, not into the wash-bowls. 



HOW TO KEEP THE JOURNAL. 



Page this journal as a continuation of the bo< k At the upper right 
hand enter the date, at the upper left hand the article of the book to be 
demonstrated by your experiment. As heading of page, write con- 
cisely and plainly the subject investigated. On the proper place, in 
the margin of the text, enter the number of the page of the journal 
where these experiments are recorded. In this manner, yon can 
readily turn from the text to the experiments, and from the experi- 
ments to the text. Never omit doing this. The author only directs 
your work. — you discover the trutl* of the laws for yourself 

Keep your journal perfectly clean and nice, write plainly and ele- 
gantly ; do not crowd words and figures together, but leave ample 
room in margin. 

Be concise and precise in all your written statements; avoid all supei- 
fluous words. Freely use proper abbreviations, such as given in 231, 
and also, the following: — 

Bp. Blowpipe. 

Ch. Charcoal. 

Sd. Soda. 

Fltr. Filtrate. 

fltr. filter. 



Pr. 


Precipitate. 


pr. 


precipitate. 


sol. 


Soluble. 


Sol. 


Solution. 


in sol. 


insoluble. 



EXPERIMENTAL DEMONSTRATIONS IN THE 
ELEMENTS OF CHEMISTRY. 



As soon as an experimental demonstration lias been performed, cuu- 
cel the corresponding number or letter in this list by a cross (X), in 
pencil, so that your teacher, at a glance, can see what experimental 
demonstrations you have completed. 

HEAT. 

Blowpipe: 23. 24 5 . 26 7. 28. 

Radiation : 33. 34 5. 41. 

Thermometer and Calorimeter : 38. 44. 45. 50. 

Fusing and Boiling: 00. 61. 63, a, b. 64, a. b. 67. 08. 

CHEMISTRY. 

Dissociation: 93, a, b, c. 94. 95.* 99. 101. 102. 104. 
Elements and Compounds : 116, a, b, c, d, e, f, g, h, k, 1. 117, a, 

b, c, d, e, f, g, h, k, 1. 
Acids and Bases: 133 4. 130 7. 141 2. 150-3, a, b, c, d. 155. 

157 8 . 159. 
Synthesis : 100, a, b. 107, a, b, c. 108, 109, 170. 
Substitution: 172-3, a, b, c, d, e, f, g, h. 174, a, b, c, d. 175, a, 

b, c, d, e, f, g, h 170. 177. ISO. 181. 
Double Decomposition: 190, a, b, c. 191. 192. 193. 190. 197. 

198. 199. 200. 201. 202. 205, a, b, c, d, e, f, g, h. 200-7, a, 

b, c, d, e, f, g, h. 208. 
Complex Processes : 213. 215.* 210. 



MINERALOGY. 

[Enter the species and variety determined after the number of genus printed.] 

GENERAL DETERMINATION : 

Elements: 1 — 2 — 3 — 4 — 5 — 

Sulphides: 11 12 — 15 18 21 — 22 — 30 - 

Sulphosalts : 31 — 41 — 45 

Oxides, Single : 01 04 — 

67 — 71 — 80 — 



168 Elements of Chemistrg and Mineralogy. 



Metallosalts : 81 82 — 83 84 88 — 90, 91. 

Sulphates: 101 111 — 130 

Phosphates : 135 — 141 — 150 — 

Nitrates : 151 — 

Borates: 161 — 165 — 171 — 



Carbonates : 181 








— 








— 200 


.Silicates : 201 — 


203 — 





— 


205 





- 207 - 


211 


— 214 - 





220 - 


221 


— 230 


— 240 


— — 












Fluorides : 271 — 


• 275 — 


281 


— 


290 


— 




Combustibles : 1 ■ 


o 


3 — 


4 


— ; 


> — 


6 



DETERMINATION OF CRYSTALS. 

Triclinic: 130 5 . 161 i. 211. 213. 221 i. 230 4 . 

Monoclinic: llli. 130 4 . 171 i. 200 i. 2ii4o :;4 . 205 ■> .;. 211 i. 

230 ■>:,. 
Rhombic: 11 a 18 1. 45 3. 101 2 3. 151 1. 181 15 16. 201 2. 205 1. 

214 is. 230,;. 240 16 7- 
Quadratic: 31 1. 01 34 c,;. 83 1 %. 220 3. 240 5. 

RhOMBOHEDRAL : 45 1 •<>. 01 l- 04 1 2. 151 ■>. 1*1 12 .-, 4 ; s. 201 1 :;. 

214 2. 230:-;. 240 s. 
Hexagonal: 71 10. 135 1 % 220 2. 230 1. 
Tesseral ; :i, It o 1 o li v d ral : 15 1 2. 41 ■>. 71 1. 81 2 3 84 1. 

207 1. 220 1. 240 4.* 27 1 1. 281 1. 
b, lie mi h edra 1: 11 1. 41 1. 165 1. 

PROBLEMS. 

Reductio 11 s, 39 — Expnnsin 11, 40 

Heat a 11 <1 C o m b u s t i o n, 46 — 47 

Heating b} r Steam, 69 Pressure of Vapors, 72, 

Steam Engin e, 78, 

Substitution, 183 — 

Each experiment performed, determination made, or problem solved, 
should be canceled on this check-list; so tbat this list, at a glance, 
shows what has been done in practice. 

Exhibit this check list to your instructor whenever new work is to 
be assigned to you. 



Journal of Experiments. 



1 09 



GENERA. 

r 


H... 




SPKCIK 


s. 




1 Ka 


Li 


Na 


Ka 








2 Xa 






Ca 




Sr 


Ba 


3 Kd 




Mg 


Zn 




Cd 


Pb 


rr 












Hg 


4 Ko 






Cu 




Ag 


Au 


5 It 




Al 


2'J 




Rh 


Ir 


6 7V 


C 
Bo 


Si 


Ti 




Pd 

Sn 


Pt 


7 


N 


P 


As 




Sb 


Bi 


8 





S 


Se 




Te 




9 X 


Fl 


CI 


Br 




lo 




r 


H.. 












2to 


ICr 


Mn 


Fe 


!N T i 


( 


I 



170 Elements of Chemistry and Mineralogy, 



GENERA. 

r r 



SPECIES. 



Ka 
Xa 

Kd 
r r 

Ko 
1'c 
Tt 



6 
X 

Y 



Li 



C 
Bo 

1ST 

O 

Fl 

H. 
Or 



Na 



Mi 



Al 
Si 

P 

S 
01 



Ka 
Ca 
Zn 

Cu 

id 

Ti 

As 
Se 
Br 



Sr 
Cd 



Ag 



Rh 
Pd 
fen 
Sb 
Te 
lo 



Ba 

Pb 

Hg 

An 

Ir 

Pt 

Bi 



Mn 



Fe 



m 



^o 



Uv 



ffiiur 




tits. 



—*r 



7\ if volaX, 



~fC y Tto-n. vo lot t . 



IrvCl 
PiPt 

W\ P \Ai it Be 

A'. &\BWo 
H Tti& 

§15Z. 



IlinricliK' Elements of Physical S<it-ii< < 
Plate a. 




81 



















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